Dictionary Thesaurus Word Dynamo Quotes Reference Translator Spanish

English plural

In the English language, nouns are inflected for grammatical number—that is, singular or plural. This article discusses the variety of ways in which English plurals are formed.

Note that phonetic transcriptions provided in this article are for Received Pronunciation and General American.

Regular plurals

The plural morpheme in English is suffixed to the end of most nouns. The plural form is usually represented orthographically by adding -s to the singular form (see exceptions below). The phonetic form of the plural morpheme is [z] by default. Examples:

boy	boys
girl	girls	,
chair	chairs	,

When the preceding sound is a voiceless consonant—such as [t], [p], or [k]—it is pronounced [s]. Examples:

cat	cats
lap	laps
clock	clocks	,

Where a noun ends in a sibilant sound—[s], [ʃ], [ʧ], [z], [ʒ], or [ʤ]—the plural is formed by adding [ɪz] (also pronounced [əz]), which is spelled -es if the word does not already end with -e:

dish	dishes
glass	glasses
judge	judges
phase	phases
witch	witches

Morphophonetically, these rules are sufficient to describe most English plurals. However, there are several complications introduced in spelling.

The -oes rule: most nouns ending in o preceded by a consonant also form their plurals by adding -es (pronounced [z]):

hero	heroes
potato	potatoes
volcano	volcanoes or volcanos

The -ies rule: nouns ending in a y preceded by a consonant usually drop the y and add -ies (pronounced [iz]). This is taught to many American and British students with the rhyme: "Change the y to i and add es":

cherry	cherries
lady	ladies

However, proper nouns (particularly those for people or places) ending in a y preceded by a consonant form their plurals regularly :

Germany	Germanys (as in The two Germanys were unified in 1990; this rule is commonly not adhered to as several book titles show, and Sicilies rather than Sicilys is the standard plural of Sicily)
Harry	Harrys (as in There are three Harrys in our office)

The rule does not apply to words that are merely capitalized common nouns:

P&O Ferries (from ferry)

Other exceptions include lay-bys and stand-bys.

Words ending in a y preceded by a vowel form their plurals regularly:

day	days
monkey	monkeys

(Money/Monies is an exception, but money can also form its plural regularly.)

Almost-regular plurals

Many nouns of foreign origin, including almost all Italian loanwords, are exceptions to the -oes rule:

canto	cantos
homo	homos
piano	pianos
portico	porticos
pro	pros
quarto (paper size)	quartos
kimono	kimonos

Many nouns ending in a voiceless fricative mutate those sounds to a voiced fricative before adding the plural ending. In the case of [f] changing to [v] the mutation is indicated in the orthography as well; also, a silent e is added in this case if the singular does not already end with -e:

bath	baths	, /bɑːθs/
house	houses	, /haʊsɪz/
mouth	mouths	, /maʊθs/
calf	calves	,
knife	knives

Some retain the voiceless consonant:

moth	moths
place	places
proof	proofs

Some can do either:

dwarf	dwarfs/dwarves
hoof	hoofs/hooves
roof	roofs/rooves (latter archaic)
staff	staffs/staves
turf	turfs/turves (latter rare)
leaf	Leafs/leaves (see footnote)

For dwarf, the common form of the plural was dwarfs—as, for example, in Walt Disney's Snow White and the Seven Dwarfs—until J. R. R. Tolkien popularized dwarves; he intended the changed spelling to differentiate the "dwarf" fantasy race in his novels from the cuter and simpler beings common in fairy tales, but his usage has since spread. Multiple astronomical dwarf stars and multiple nonmythological short human beings, however, remain dwarfs. For staff in the sense of "a body of employees", the plural is always staffs; otherwise, both staffs and staves are acceptable, except in compounds; such as flagstaffs. Staves is rare in North America except in the sense of "magic rod." The stave of a barrel or cask is a back-formation from staves, which is its plural. (See the Plural to singular by back-formation section below.) For leaf, the former refers specifically to the Toronto Maple Leafs ice hockey team, while the latter is the term used for the plural of the plant part in general. (See the collective nouns section below.)

Irregular plurals

There are many other less regular ways of forming plurals, usually stemming from older forms of English or from foreign borrowings.

Nouns with identical singular and plural

Some nouns spell their singular and plural exactly alike; some linguists regard these as regular plurals. Many of these are the names of animals:

deer

fish/fishes

moose

sheep

swine

The plural deers is listed in some dictionaries, but is considered by many to be an error.

Fish does have a regular plural form, but it differs in meaning from the unmarked plural; fishes refers to several species or other taxonomic types, while fish (plural) is used to describe multiple individual animals: one would say "the order of fishes," but "five fish in an aquarium." The plural fishes is found in the King James Bible, in the miracle of the loaves and fishes, for example, and is sometimes used for rhetorical emphasis, as in phrases like sleep with the fishes.

Other nouns that have identical singular and plural forms include:

aircraft

blues

cannon (sometimes cannons)

head

Referring to individual songs in the blues musical style: "play me a blues"; "he sang three blues and a calypso"
Referring, in the plural, to animals in a herd: "fifty head of cattle"

Irregular -(e)n plurals

The plural of a few nouns can also be formed from the singular by adding -n or -en, stemming from the obsolete Old English weak declension:

ox	oxen	(particularly when referring to a team of draft animals, sometimes oxes e.g. in a metaphorical sense)
cow	kine	(archaic/regional; actually earlier plural "kye" [cf. Scots "kye" - "cows"] plus -en suffix, forming a double plural)
egg	eyren/eggys	(rare/dialectal Northern England & Scotland)
eye	eyen	(rare, found in some regional dialects)
shoe	shoon	(rare/dialectal)
house	housen	(rare/dialectal, used by Rudyard Kipling in Puck of Pook's Hill)
hose	hosen	(rare/archaic, used in King James Version of the Bible)
brother	brethren	(archaic plural of brother; earlier "brether" plus -en suffix, forming a double plural; now used in fraternal order)
child	children	(actually earlier plural "cildra/cildru" plus -en suffix, forming a double plural)

The word box, referring to a computer, is semi-humorously pluralized boxen in the Leet dialect. Multiple Vax computers, likewise, are sometimes called Vaxen particularly if operating as a cluster, but multiple Unix systems are usually Unices (see Irregular plurals of foreign origin below).

The word sistren, referring to Christian sisters [modeled on brethren], is also semi-humorously pluralized.

Umlaut plurals

The plural is sometimes formed by simply changing the vowel sound of the singular, in a process called umlaut (these are sometimes called mutated plurals):

foot	feet
goose	geese
louse	lice
man	men
mouse	mice
tooth	teeth
woman	women

Mouse is sometimes pluralized mouses in discussions of the computer mouse; however, mice is just as common.

Mongoose, however, has the plural mongooses.

Irregular plurals from Latin and Greek

English has borrowed a great many words from Latin and Classical Greek. The general trend with loanwords is toward what is called Anglicization or naturalization, that is, the re-formation of the word and its inflections as normal English words. Many nouns (particularly ones from Latin) have retained their original plurals for some time after they are introduced. Other nouns have become Anglicized, taking on the normal "s" ending. In some cases, both forms are still competing.

The choice of a form can often depend on context: for a librarian, the plural of appendix is appendices (following the original language); for physicians, however, the plural of appendix is appendixes. Likewise, a radio engineer works with antennas and an entomologist deals with antennae. Choice of form can also depend on the level of discourse: correctly formed Latin plurals are found more often in academic and scientific contexts, whereas in daily speech the anglicized forms are more common. In the following table, the Latin plurals are listed, together with the Anglicized forms when they are more common.

Final a becomes -ae (also -æ), or just adds -s:

alumna	alumnae
formula	formulae/formulas
encyclopædia	encyclopædias (encyclopædiae is rare)

Final ex or ix becomes -ices (pronounced [ɪˌsiːz] or [əˌsiz]), or just adds -es:

index	indices	/ˈɪndɪˌsiːz/	or indexes
matrix	matrices	/ˈmeɪtɹɪˌsiːz/
vertex	vertices	/ˈvɜːtɪˌsiːz/,/ˈvɝtɪˌsiːz/

Some people treat process as if it belonged to this class, pronouncing processes /ˈpɹɑsɪˌsiːz/ instead of standard /ˈpɹɑsɛsɪz/. Since the word comes from Latin processus, whose plural is again processus, but now with a long u (fourth declension), this pronunciation is without etymological basis.

Final is becomes es (pronounced [ˌiːz]):

axis	axes	/ˈækˌsiːz/
crisis	crises	/ˈkɹaɪˌsiːz/
testis	testes	/ˈtɛsˌtiːz/

Note that axes, the plural of axis, is pronounced differently from axes (/ˈæksɪz/), the plural of ax(e).

Final ies remains unchanged:

series	series
species	species

Final on becomes -a:

automaton	automata
criterion	criteria
phenomenon	phenomena (more below)
polyhedron	polyhedra

Final um becomes -a, or just adds -s:

addendum	addenda
agendum (obsolete, not listed in most dictionaries)	agenda means a "list of items of business at a meeting" and has the plural agendas
datum	data (Now usually treated as a singular mass noun in both informal and educated usage, but usage in scientific publications shows a strong UK/US divide. U.S. usage prefers treating data in the singular in all contexts, including serious and academic publishing. UK usage now widely accepts treating data as singular in standard English, including educated everyday usage at least in non-scientific use. UK scientific publishing usually still prefers treating it as a plural. Some UK university style guides recommend using data for both singular and plural use and some recommend treating it only as a singular in connection with computers. ) In engineering, drafting, surveying, and geodesy, and in weight and balance calculations for aircraft, a datum (plural datums or data) is a reference point, surface, or axis on an object or the earth’s surface against which measurements are made.
forum	fora/forums
medium	media (in communications and computers; now often treated as a singular mass noun)/ mediums (spiritualists, or items of medium size etc.)
memorandum	memoranda/memorandums

Final us becomes -i (second declension, [aɪ]) or -era or -ora (third declension), or just adds -es (especially in fourth declension, where it would otherwise be the same as the singular):

alumnus	alumni
corpus	corpora
focus	foci
genus	genera
prospectus	prospectuses (plural prospectus is rare)
radius	radii
viscus	viscera

Virus had no plural ending in Latin; the plural in English is usually viruses. See plural of virus.

cactus	cactuses/cacti (in Arizona many people avoid either choice with cactus as both singular and plural.)
fungus	fungi
hippopotamus	hippopotamuses/hippopotami
octopus	octopuses (note: octopi also occurs, although it is strictly speaking unfounded , because it is not a Latin noun of the second declension, but rather a Latinized form of Greek ὀκτώπους. The theoretically correct form octopodes is rarely used.)
platypus	platypuses (same as octopus: platypi occurs but is etymologically incorrect, and platypodes, while technically correct, is even rarer than octopodes)
terminus	termini/terminuses
uterus	uteri/uteruses

Colloquial usages based in a humorous fashion on the second declension include Elvii to refer to multiple Elvis impersonators and Loti, used by petrolhead to refer to Lotus automobiles in the plural.

Final as in one case of a noun of Greek origin changes to -antes:

Atlas	Atlantes (statues of the hero); but
atlas	atlases (map collections)

Final ma in nouns of Greek origin can add -ta, although -s is usually also acceptable, and in many cases more common.

stigma	stigmata/stigmas
stoma	stomata/stomas
schema	schemata/schemas
dogma	dogmata/dogmas
lemma	lemmata/lemmas

Irregular plurals from other languages

Some nouns of French origin add -x:

beau	beaux
bureau	bureaus or bureaux
château	châteaux

Foreign terms may take native plural forms, especially when the user is addressing an audience familiar with the language. In such cases, the conventionally formed English plural may sound awkward or be confusing.

Nouns of Slavic origin add -a or -i according to native rules, or just -s:

kniazhestvo	kniazhestva/kniazhestvos
kobzar	kobzari/kobzars
oblast	oblasti/oblasts

Nouns of Hebrew origin add -im or -ot (generally m/f) according to native rules, or just -s:

cherub	cherubim/cherubs
matzah	matzot/matzahs
seraph	seraphim/seraphs

Note that ot is pronounced os in the Ashkenazi dialect.

Many nouns of Japanese origin have no plural form and do not change:

benshi	benshi
otaku	otaku
samurai	samurai

However, other nouns such as kimonos, ninjas, futons, and tsunamis are more often seen with a regular English plural.

In New Zealand English, nouns of Māori origin can either take an -s or have no separate plural form. Words more connected to Māori culture and used in that context tend to retain the same form, while names of flora and fauna may or may not take an -s, depending on context. Many as more correct regard omission:

kiwi	kiwi/kiwis
kowhai	kowhai/kowhais
Māori	Māori/(occasionally Māoris)
marae	marae
tui	tuis/tui
waka	waka

When referring to the bird, kiwi may or may not take an -s; when used as an informal term for a New Zealander, it always takes an -s.
Māori, when referring to a person of that ethnicity, does not usually take an -s. Many speakers avoid the use of Māori as a noun, and instead use it only as an adjective.

In Canada and Alaska, some words borrowed from Inuktitut retain traditional plurals (see also Plurals of names of peoples, below):

Inuk	Inuit
inukshuk	inukshuit

Nouns from languages other than the above generally form plurals as if they were native English words:

canoe	canoes
cwm	cwms (Welsh valley)
igloo	igloos
kangaroo	kangaroos
kayak	kayaks
kindergarten	kindergartens
pizza	pizzas
sauna	saunas

Words better known in the plural

Some words of foreign origin are much better known in the plural; usage of the original singular may be considered pedantic or actually incorrect or worse by some speakers. In common usage, the original plural is considered the singular form. In many cases, back-formation has produced a regularized plural.

Original singular	Original plural/ common singular	Common plural
thou	you	you
agendum	agenda	agendas
alga	algae	algae
biscotto	biscotti	biscotti
candelabrum	candelabra	candelabras
datum	data	data (mass noun)
graffito	graffiti	graffiti (mass noun)
insigne	insignia	insignias
opus	opera	operas
panino	panini	paninis (currently gaining use)
paparazzo	paparazzi	paparazzi

An agenda commonly is used to mean a list of agenda. A single piece of data is sometimes referred to as a data point. In engineering, drafting, surveying, and geodesy, and in weight and balance calculations for aircraft, a datum (plural datums or data) is a reference point, surface, or axis on an object or the earth’s surface against which measurements are made.

Some plural nouns are used as such—invariably being accompanied by a plural verb form—while their singular forms are rarely encountered:

nuptial	nuptials
phalanx	phalanges
tiding	tidings
victual	victuals
viscus	viscera

In medical terminology, a phalanx is any bone of the finger or toe. A military phalanx is pluralized phalanxes.

A related phenomenon is the confusion of a foreign plural for its singular form:

criterion	criteria
phenomenon	phenomena
consortium	consortia
symposium	symposia

Magazine was derived from Arabic via French. It was originally plural, but in English, it is always regarded as singular.

Plurals of numbers

English, like some other languages, treats large numerals as nouns (cf. "there were ten soldiers" and "there were a hundred soldiers"). Thus, dozens is preferred to tens, while hundreds and thousands are also completely acceptable.

Plurals of numbers differ according to how they are used. The following rules apply to dozen, score, hundred, thousand, million, and similar terms:

When modified by a number, the plural is not inflected, that is, has no -s added. Hence one hundred, two hundred, etc. For vaguer large numbers, one may say several hundred or many hundreds.
When used alone, or followed by a prepositional phrase, the plural is inflected: dozens of complaints, scores of people. However, either complaints by the dozen or complaints by the dozens is acceptable (although differing in meaning).
The preposition of is used when speaking of nonspecific items identified by pronouns: two hundred of these, three dozen of those. The of is not used for a number of specific items: three hundred oriental rugs. However, if the pronoun is included with the specific item, the of is used: five million of those dollar bills.

Nouns used attributively

Nouns used attributively to qualify other nouns are generally in the singular, even though for example, a dog catcher catches more than one dog, and a department store has more than one department. This is true even for some binary nouns where the singular form is not found in isolation, such as trouser press or scissor kick. It is also true where the attribute noun is itself qualified with a number, such as a twenty-dollar bill, a ten-foot pole or a two-man tent. The plural is used for pluralia tantum nouns; a glasses case is for eyeglasses, while a glass case is made of glass. The plural may also be used to emphasise the plurality of the attribute, especially in British English: a careers advisor, a languages expert. The plural is also more common with irregular plurals for certain attributions: women killers are women, whereas woman killers kill women.

Defective nouns

Some nouns have no singular form. Such a noun is called a plurale tantum (see also Words better known in the plural above):

billiards, clothes, measles, thanks, vittles

Some of these do have singular adjective forms, such as billiard ball. In addition, some are treated as singular in construction, e.g., "billiards is a game played on a table with billiard balls and a cue", "measles is an infectious disease". Thanks is usually treated as plural.

A particular set of nouns, describing things having two parts, comprises the major group of pluralia tantum in modern English:

pants, pliers, scissors, shorts, trousers, glasses (a pair of)

Note that these words are interchangeable with a pair of scissors, a pair of trousers, and so forth. In the U.S. fashion industry it is common to refer to a single pair of pants as a pant —though this is a back-formation, the English word (deriving from the French pantalon) was originally singular. In the same field, one half of a pair of scissors separated from the other half is, rather illogically, referred to as a half-scissor. Tweezers used to be part of this group, but tweezer has come into common usage since the second half of the twentieth century.

Mass nouns (or uncountable nouns) do not represent distinct objects, so the singular and plural semantics do not apply in the same way. Some examples:

Abstract nouns

goodness, idleness, honesty, deceit, freshness, bitterness, information, obscurity, wisdom, cunning

Arts and sciences

chemistry, geometry, surgery, mechanics, optics, blues, jazz, rock and roll, impressionism, surrealism

Chemical elements and other physical entities:

antimony, gold, oxygen, equipment, furniture, gear, species, air, water, sand, traffic

Referring to the musical style as a whole.

Some mass nouns can be pluralized, but the meaning thereof may change slightly. For example, when I have two pieces of sand, I do not have two sands; I have sand. There is more sand in your pile, not more sands. However, there could be many “sands of Africa”—either many distinct stretches of sand, or distinct types of sand of interest to geologists or builders, or simply the allusive sands of Africa.

It is rare to pluralize furniture in this way. Nor would information be so treated, except in the case of criminal informations, which are prosecutor's briefs similar to indictments.

There is only one class of atoms called oxygen, but there are several isotopes of oxygen, which might be referred to as different oxygens. In casual speech, oxygen might be used as shorthand for "oxygen atoms", but in this case, it is not a mass noun, so it is entirely sensible to refer to multiple oxygens in the same molecule.

One would interpret Bob's wisdoms as various pieces of Bob's wisdom (that is, don't run with scissors, defer to those with greater knowledge), deceits as a series of instances of deceitful behavior (lied on income tax, dated my wife), and the different idlenesses of the worker as plural distinct manifestations of the mass concept of idleness (or as different types of idleness, "bone lazy" versus "no work to do").

Specie and species make a fascinating case. Both words come from a Latin word meaning "kind", but they do not form a singular-plural pair; they are separate nouns. Coins, such as nickels, euros (see Linguistic issues concerning the euro), and cents are specie, but there is no plural. The idea is "payment in kind". Moreover, species, the "kinds of living things", is the same in singular and plural.

Plurals of compound nouns

The majority of English compound nouns have one basic term, or head, with which they end, and are pluralized in typical fashion:

able seaman	able seamen
headbanger	headbangers
yellow-dog contract	yellow-dog contracts

A compound that has one head, with which it begins, usually pluralizes its head:

attorney general	attorneys general
bill of attainder	bills of attainder
court martial	courts martial
governor-general	governors-general
passerby	passersby
ship of the line	ships of the line
son-in-law	sons-in-law
minister-president	ministers-president
knight-errant	knights-errant
procurator fiscal (in Scotland)	procurators fiscal

It is common in informal speech to instead pluralize the last word in the manner typical of most English nouns, but in edited prose, the forms given above are preferred.

If a compound can be thought to have two heads, both of them tend to be pluralized when the first head has an irregular plural form:

man-child	men-children
manservant	menservants
woman doctor	women doctors

Two-headed compounds in which the first head has a standard plural form, however, tend to pluralize only the final head:

city-state	city-states
nurse-practitioner	nurse-practitioners
scholar-poet	scholar-poets

In military usage, the term general, as part of an officer's title, is etymologically an adjective, but it has been adopted as a noun and thus a head, so compound titles employing it are pluralized at the end:

brigadier general	brigadier generals
major general	major generals

For compounds of three or more words that have a head (or a term functioning as a head) with an irregular plural form, only that term is pluralized:

man-about-town	men-about-town
man-of-war	men-of-war
woman of the street	women of the street

For many other compounds of three or more words with a head at the front—especially in cases where the compound is ad hoc and/or the head is metaphorical—it is generally regarded as acceptable to pluralize either the first major term or the last (if open when singular, such compounds tend to take hyphens when plural in the latter case):

ham on rye	hams on rye/ham-on-ryes
jack-in-the-box	jacks-in-the-box/jack-in-the-boxes
jack-in-the-pulpit	jacks-in-the-pulpit/jack-in-the-pulpits

With a few extended compounds, both terms may be pluralized—again, with an alternative (which may be more prevalent, e.g., heads of state):

head of state	heads of states/heads of state
son of a bitch	sons of bitches/sons-of-a-bitch

With extended compounds constructed around o', only the last term is pluralized (or left unchanged if it is already plural):

cat-o'-nine-tails	cat-o'-nine-tails
jack-o'-lantern	jack-o'-lanterns
will-o'-the-wisp	will-o'-the-wisps

Compounds from the French

Many English compounds have been borrowed directly from the French, and these generally follow a somewhat different set of rules. French-loaned compounds with a head at the beginning tend to pluralize both words, according to French practice:

agent provocateur	agents provocateurs
entente cordiale	ententes cordiales
fait accompli	faits accomplis
idée fixe	idées fixes

For compounds adopted directly from the French where the head comes at the end, it is generally regarded as acceptable either to pluralize both words or only the last:

beau geste	beaux gestes/beau gestes
belle époque	belles époques/belle époques
bon mot	bons mots/bon mots
bon vivant	bons vivants/bon vivants

French-loaned compounds longer than two words tend to follow the rules of the original language, which usually involves pluralizing only the head at the beginning:

aide-de-camp	aides-de-camp
cri de coeur	cris de coeur
coup d'état	coups d'état
tour de force	tours de force

but:

tête-à-tête

tête-à-têtes

A distinctive case is the compound film noir. For this French-loaned artistic term, English-language texts variously use as the plural films noirs, films noir, and, most prevalently, film noirs. The 11th edition of the standard Merriam-Webster's Collegiate Dictionary (2006) lists film noirs as the preferred style. Three primary bases may be identified for this:

Unlike other compounds borrowed directly from the French, film noir is used to refer primarily to English-language cultural artifacts; a typically English-style plural is thus unusually appropriate.
Again, unlike other foreign-loaned compounds, film noir refers specifically to the products of popular culture; consequently, popular usage holds more orthographical authority than is usual.
English has adopted noir as a stand-alone noun in artistic contexts, leading it to serve as the lone head in a variety of compounds (e.g., psycho-noir, sci-fi noir).

See also the headless nouns section below.

Plurals (and singulars) of headless nouns

In The Language Instinct, linguist Steven Pinker discusses what he calls "headless words," typically bahuvrihi compounds, like lowlife and Red Sox, in which life and sox are not heads semantically; that is, a lowlife is not a type of life, nor are Red Sox a group of similarly colored socks. When the common form of such a word is singular, it is treated as if it has a regular plural, even if the final constituent of the word is usually pluralized in a nonregular fashion. Thus, more than one lowlife are lowlifes, not "lowlives." A related process can be observed with the compound maple leaf, pluralized in its common-noun form as maple leaves; when it is adopted as the name of an ice-hockey team, its plural becomes Maple Leafs. Other examples include:

flatfoot	flatfoots
sabertooth	sabertooths
still life	still lifes
tenderfoot	tenderfoots

An exception is Blackfoot, of which the plural can be Blackfeet, though that form of the name is officially rejected by the Blackfoot First Nations of Canada.

Where words have taken on completely new meanings, irregular plurals may become regularized. Antennas is the accepted plural of antenna when it refers to electronic equipment, in contrast to antennae for arthropod feelers. The computer mouse is sometimes considered headless and pluralized as mouses, but also often as mice; in contrast to the compound headless words just discussed, there is a considerably stronger metaphorical relationship in this case, with many computer pointing devices resembling rodents with tails.

In other cases, the common form of a headless word is a nonregular plural; when such a word lacks a terminal s, it is treated as defective, thus making the singular version of the word identical: an individual member of the Boston baseball team is a Red Sox, just as all twenty-five are; one Chicago White Sox is a White Sox.

Related collective nouns

Sports team names like those discussed above—as well as more grammatically ordinary names such as Reds, Knicks, and Canadiens, and straightforward compound names such as Blue Jays—form a particular set of collective nouns. Closely related to the class of essentially plural headless nouns typified by Red Sox are the growing number of orthographically singular sports team names that may be classified as examples of a special type of collective noun—one that (a) has identical terms for both the collective and an individual thereof (as with the essentially plural headless noun) but (b) is not used as a counting noun beyond the singular. Two examples include the name of the Miami NBA team—Heat—and the name of the Colorado NHL team—Avalanche. While heat is a mass noun, whereas avalanche is a normal counting noun, in the context of a team name, both words operate as this special type of collective noun. Just as with the Sox, any one of the twelve current members of Miami's pro basketball squad is a Heat; similarly, any individual member of the Colorado Avalanche is an Avalanche. However, where one may say, for instance, that "two Red Sox struck out" or "four White Sox homered," the equivalent term is invariably used as an adjective when referring to multiple players of one of the teams named in this increasingly popular way: "two Heat players fought" or "four Avalanche players scored" (Avalanche followers have a little more flexibility, with "Avs" as the team's unofficial, but widely used nickname). Other examples include:

NHL	WNBA
Tampa Bay Lightning	Indiana Fever
Minnesota Wild	New York Liberty
NBA	Minnesota Lynx
Utah Jazz	Phoenix Mercury
Orlando Magic	Detroit Shock
Oklahoma City Thunder	Chicago Sky
MLS	Charlotte Sting
Columbus Crew	Seattle Storm
Houston Dynamo	Connecticut Sun
Chicago Fire	AFL (Australian Football League)
Los Angeles Galaxy	Port Adelaide Power
New England Revolution
D.C. United

Note that in not every case above is it certain that the name is ever used in its noun form to refer to anything but the collective—i.e., not even to an individual player; in other cases, it is possible that the name is sometimes used in its noun form (with or without a terminal s appended) to refer to multiple players, short of the whole collective.

An exceptional case is that of the St. Louis Blues hockey team. The club is named after the song "St. Louis Blues," which makes the team name Blues an irregularly pluralized word to begin with—one whose plural is identical to its singular. By this reckoning, then, an individual team member would also be a "Blues." However, because the name is spelled like a regular plural, its use as a collective noun leads to a process of back-formation, with the result that a single player on the team is known as a Blue. The club name's distinctive orthographical nature further allows it to be used freely as a counting noun, so that one may speak of, for instance, "two Blues in the penalty box."

Pinker discusses a case that could be construed as opposite, that of the Florida Marlins baseball team. Describing how the issue was raised by talk show host David Letterman, Pinker asks, Why is the name Marlins "given that those fish are referred to in the plural as marlin?" An analogous question could be asked about the Maple Leafs. Pinker's answer comes down to this: "A name is not the same thing as a noun. Consequently, names (and nouns that derive from names) based on nouns with irregular plurals do not acquire them—though, as we see with Red Sox, new irregularities may arise.

Nouns with multiple plurals

Some nouns have two plurals, one used to refer to a number of things considered individually, the other to refer to a number of things collectively. In some cases, one of the two is nowadays archaic or dialectal.

brother	brothers	brethren
cannon	cannons	cannon
child	children	childer
cloth	cloths	clothes
cow	cows	kine
die	dice	dies
fish	fish	fishes
iris (plant)	iris	irises
penny	pennies	pence
person	persons	people
pig	pigs	swine
sow	sows	swine

Brethren refer to members of a monastic order, while brothers are family members and related by blood. Childer has all but disappeared, but can still be seen in Childermas (Innocents' Day). Clothes refers collectively to all of a household's washable cloth articles, but is now used almost exclusively of garments. Kine is still used in some rural English dialects. Dies is used as the plural for die in the sense of a mould; dice as the plural (and increasingly as the singular) in the sense of a small random number generator. Dice is also the accepted plural form of die in the semiconductor industry. Fish: the plural for one species of fish, or caught fish, is fish, but for live fish of many species, in poetic usage, and in some dialects fishes is used. For multiple plants, iris is used, but irises is used for multiple blossoms. If you have several (British) one-penny pieces you have several pennies. Pence is used for an amount of money, which can be made up of a number of coins of different denominations: one penny and one five-penny piece are together worth six pence. The suffixed minor currency unit of 'p' (/pi/) is often vocalised, where such small divisions of currency are discussed in common speech, and used for both the singular and the 'amount plural', but 'number plurals' build upon the base values and any omission of the unit shifts the plural to the coin's numerator (e.g. "I have a one /pi/ and three twenty /piz/ and two fifties in my pocket. I cannot believe I only have one pound, sixty-one /pi/ left after last night."). In written speech, a number of coins might be "two 10ps", although those that prefer to use apostrophes for initialisms may decide to use the "two 10p's" variant. Penny and pennies also refer to one or more U.S. one-cent pieces, though in American usage, a nickel is worth five cents, not five pence. The word people is usually treated as the suppletive plural of person (one person, many people). However, in legal and other formal contexts, the plural of person is persons; furthermore, people can also be a singular noun with its own plural (for example, "We are many persons, from many peoples").

Plurals of symbols and initialisms

Individual letters and abbreviations whose plural would be ambiguous if only an -s were added are pluralized by adding -'s.

mind your p's and q's

A.A.'s and B.A.'s

the note had three PS's

Opinion is divided on whether to extend this use of the apostrophe to related but nonambiguous cases, such as the plurals of numerals (e.g., 1990's vs. 1990s) and words used as terms (e.g., "his writing uses a lot of but's" vs. "his writing uses a lot of buts"). Some writers favor the use of the apostrophe as consistent with its application in ambiguous cases; others say it confuses the plural with the possessive -'s and should be avoided whenever possible in pluralization, a view with which The Chicago Manual of Style concurs.

English and many other European languages form the plural of a one-letter abbreviation by doubling it: p. ("page"), pp. ("pages"); l. ("line"), ll. ("lines"). These abbreviations are used in literary work, such as footnotes and bibliographies.

Acronyms are initialisms used as if they are words. Clearly, it is not desirable to pluralize the acronym laser as laser's. Thus, the most consistent approach for pluralizing acronyms is to simply add a lowercase -s as a suffix. This works well even for acronyms ending with an s, as with CASs (pronounced "kazzes"), while still making it possible to use the possessive form (-'s) for acronyms without confusion. The traditional style of pluralizing single letters with -'s was naturally extended to acronyms when they were commonly written with periods. This form is still preferred by some people for all initialisms and thus -'s as a suffix is often seen in informal usage.

Plural to singular by back-formation

Some words have unusually formed singulars and plurals, but develop "normal" singular-plural pairs by back-formation. For example, pease (modern peas) was in origin a singular with plural peasen. However, pease came to be analysed as plural by analogy, from which a new singular pea was formed; the spelling of pease was also altered accordingly. Similarly, termites and primates were the three-syllable plurals of termes and primas; these singulars were lost, however, and the plural forms reduced to two syllables. Syringe is a back-formation from syringes, itself the plural of syrinx, a musical instrument. Cherry is from Norman French cherise. Finally, phases was once the plural of phasis, but the singular is now phase.

Kudos is a singular Greek word meaning praise, but is often taken to be a plural. At present, however, kudo is considered an error, though the usage is becoming more common as kudos becomes better known. The name of the Greek sandwich style gyros is, increasingly, undergoing a similar transformation.

The singular form of Spanish tamales is tamal ([taˈmal]). The anglicized version of tamales is and the back-formed singular is tamale /təˈmɑːliː/).

The term, from Latin, for the main upper arm flexor in the singular is the biceps muscle (from biceps brachii); however, many English speakers take it to be a plural and refer to the muscle of only one arm, by back-formation, as a bicep. The correct—although very seldom used—Latin plural would be bicipites.

The word sastrugi (hard ridges on deep snow) is of Russian origin and its singular is sastruga; but the imaginary Latin-type singular sastrugus has sometimes been used.

Plurals of names of peoples

There are several different rules for this.

In discussing peoples whose demonym takes -man or -woman, there are three options: pluralize to -men or -women if referring to individuals, and use the root alone if referring to the whole nation, or add people.

Dutchman Dutchwoman	Dutchmen Dutchwomen	the Dutch
Englishman Englishwoman	Englishmen Englishwomen	the English
Frenchman Frenchwoman	Frenchmen Frenchwomen	the French
Irishman Irishwoman	Irishmen Irishwomen	the Irish
Scotsman Scotswoman	Scotsmen Scotswomen	the Scots
Welshman Welshwoman	Welshmen Welshwomen	the Welsh

One can say "a Scots(wo)man" or "a Scot", "Scots(wo)men", "Scottish people", or "Scots," and "the Scottish" or "the Scots". (Scotch is considered old fashioned.)

Several peoples have names that are simple nouns and can be pluralized by the addition of either -s or -ish (the later case often calls for the elimination of terminal letters so the pluralizing suffix can be connected directly with the last consonant of the root):

Dane	Danes	the Danes the Danish
Finn	Finns	the Finns the Finnish
Spaniard	Spaniards	the Spaniards the Spanish (much more common)
Swede	Swedes	the Swedes the Swedish

Names of peoples that end in -ese take no plural:

Chinese	Chinese Chinese people	the Chinese
Japanese	Japanese Japanese people	the Japanese

Other names of peoples that have no plural form include Swiss and Québécois.

Most names for Native Americans are not pluralized:

Blood

Hopi

Iroquois

Mi'kmaq

Ojibwa

Sioux

Some exceptions include Algonquins, Aztecs, Chippewas, Crees, Hurons, Mohawks, and Oneidas. Note also the following words borrowed from Inuktitut:

Inuk	Inuit
Iqalummiuq	Iqalummiut ("inhabitant of Iqaluit")
Nunavimmiuq	Nunavimmiut ("inhabitant of Nunavik")
Nunavummiuq	Nunavummiut ("inhabitant of Nunavut")

Names of most other peoples of the world are pluralized using the normal English rules.

Discretionary plurals

A number of words like army, company, crowd, fleet, government, majority, mess, number, pack, and party may refer either to a single entity or the members of the set that compose it. Thus, as H. W. Fowler describes, in British English they are "treated as singular or plural at discretion"; Fowler notes that occasionally a "delicate distinction" is made possible by discretionary plurals: "The Cabinet is divided is better, because in the order of thought a whole must precede division; and The Cabinet are agreed is better, because it takes two or more to agree. Also in British English, names of towns and countries take plural verbs when they refer to sports teams but singular verbs when they refer to the actual place: England are playing Germany tonight refers to a football game, but England is the most populous country of the United Kingdom refers to the country. In North American English, such words are invariably treated as singular.

Snob plurals

Another type of irregular plural occurs in the register of the English upper classes in the context of field sports, where the singular form is used in place of the plural, as in "two lion" or "five pheasant". Eric Partridge refers to these as "snob plurals" and conjectures that they may have developed by analogy with the common English irregular plural animal words "deer", "sheep" and "trout".

The term snob plurals can be applied more generally to uses of forms of pluralization characterized, first, by their departure from the standard English rule of adding -(e)s, and, second, by the likelihood they are being so used to enhance the status of the speaker. While speaking to a group of monolingual Anglophone friends, someone talking about a recent trip to Russia who says, "We visited five oblasti," is most likely using a snob plural. Latinate plurals for nouns of Greek origin mentioned earlier in this article are often employed as snob plurals— cacti, for example, or hippopotami—although for substantial numbers of speakers, they are simply the unmarked usages. The use of nonstandard plurals can be one convenient way to communicate the claim that the speaker has a certain level of knowledge associated with sophistication and, more generally, prestige. Because the pragmatics of this usage are heavily dependent on context, it is impossible to say that a particular use of pluralization is, or is not, a snob plural in the absence of situational information. Someone speaking at an academic conference to fellow Slavicists might use oblasti without the expectation of enhanced social status and, therefore, not be using a snob plural (on the other hand, the speaker might fear a loss of social status for using oblasts). Articles in encyclopedias are, overall, written for the general reader and avoid forms of plural that would likely confuse those not already familiar with the topic.