The -oes rule: most nouns ending in o preceded by a consonant also form their plurals by adding -es (pronounced [z]):
|volcano||volcanoes or volcanos|
|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)|
|P&O Ferries (from ferry)|
Words ending in a y preceded by a vowel form their plurals regularly:
|quarto (paper size)||quartos|
Some retain the voiceless consonant:
|roof||roofs/rooves (latter archaic)|
|turf||turfs/turves (latter rare)|
|leaf||Leafs/leaves (see footnote)|
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:
|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)|
|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 sistren, referring to Christian sisters [modeled on brethren], is also semi-humorously pluralized.
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):
Mouse is sometimes pluralized mouses in discussions of the computer mouse; however, mice is just as common.
Mongoose, however, has the plural mongooses.
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.
|encyclopædia||encyclopædias (encyclopædiae is rare)|
|phenomenon||phenomena (more below)|
|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.
|medium|| media (in communications and computers; now often treated as a singular mass noun)/|
mediums (spiritualists, or items of medium size etc.)
|prospectus||prospectuses (plural prospectus is rare)|
|cactus||cactuses/cacti (in Arizona many people avoid either choice with cactus as both singular and plural.)|
|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)|
|Atlas||Atlantes (statues of the hero); but|
|atlas||atlases (map collections)|
|bureau||bureaus or bureaux|
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.
|cwm||cwms (Welsh valley)|
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/|
|datum||data||data (mass noun)|
|graffito||graffiti||graffiti (mass noun)|
|panino||panini||paninis (currently gaining use)|
Some plural nouns are used as such—invariably being accompanied by a plural verb form—while their singular forms are rarely encountered:
A related phenomenon is the confusion of a foreign plural for its singular form:
Magazine was derived from Arabic via French. It was originally plural, but in English, it is always regarded as singular.
Plurals of numbers differ according to how they are used. The following rules apply to dozen, score, hundred, thousand, million, and similar terms:
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:
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:
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.
|able seaman||able seamen|
|yellow-dog contract||yellow-dog contracts|
|attorney general||attorneys general|
|bill of attainder||bills of attainder|
|court martial||courts martial|
|ship of the line||ships of the line|
|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:
|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:
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:
|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|
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):
|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:
|cri de coeur||cris de coeur|
|coup d'état||coups d'état|
|tour de force||tours de force|
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:
See also the headless nouns section below.
|still life||still lifes|
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.
|Tampa Bay Lightning||Indiana Fever|
|Minnesota Wild||New York Liberty|
|Utah Jazz||Phoenix Mercury|
|Orlando Magic||Detroit Shock|
|Oklahoma City Thunder||Chicago Sky|
|Columbus Crew||Seattle Storm|
|Houston Dynamo||Connecticut Sun|
|Chicago Fire||AFL (Australian Football League)|
|Los Angeles Galaxy||Port Adelaide Power|
|New England Revolution|
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.
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.
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.
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.
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|
|Finn||Finns|| the Finns|
|Spaniard||Spaniards|| the Spaniards|
the Spanish (much more common)
|Swede||Swedes|| the Swedes|
Most names for Native Americans are not pluralized:
Some exceptions include Algonquins, Aztecs, Chippewas, Crees, Hurons, Mohawks, and Oneidas. Note also the following words borrowed from Inuktitut:
|Iqalummiuq||Iqalummiut ("inhabitant of Iqaluit")|
|Nunavimmiuq||Nunavimmiut ("inhabitant of Nunavik")|
|Nunavummiuq||Nunavummiut ("inhabitant of Nunavut")|
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.