Monolexemic color words are composed of individual lexemes, such as "red", "brown", or "olive". Compound color words make use of adjectives (e.g. "light brown", "sea green") or multiple basic color words (e.g. "yellow-green").
There are many different dimensions by which color varies. For example, hue (red vs. orange vs. blue), saturation ("deep" vs. "pale"), and brightness or intensity make up the HSI color space. The adjective "fluorescent" in English refers to moderately high brightness with strong color saturation. Pastel refers to colors with high brightness and low saturation.
Some phenomena are due to related optical effects, but may or may not be described separately from the color name. These include gloss (high-gloss shades are sometimes described as "metallic"; this is also a distinguishing feature of gold and silver), iridescence or goniochromism (angle-dependent color), dichroism (two-color surfaces), and opacity (solid vs. translucent).
Different cultures have different terms for colors, and may also assign some color names to slightly different parts of the human color space: for instance, the Chinese character 青 (rendered as qīng in Mandarin and ao in Japanese) has a meaning that covers both blue and green; blue and green are traditionally considered shades of "青." In more contemporary terms, they are 藍 (lán, in Mandarin) and 綠 (lǜ, in Mandarin) respectively. Japanese also has two terms that refer specifically to the color green, 綠 (midori which is derived from the classical Japanese descriptive verb midoru 'to be in leaf, to flourish' in reference to trees) and グリーン (guriin, which is derived from the English word 'green'). However, in Japan, although the traffic lights have the same colored lights that other countries have, the green light is called using the same word for blue, "aoi", because green is considered a shade of aoi, similarly green variants of certain fruits and vegetable such as green apples, green shiso (as opposed to red apples and red shiso) will be described with the word "aoi".
Similarly, languages are selective when deciding which hues are split into different colors on the basis of how light or dark they are. English splits some hues into several distinct colors according to lightness: such as red and pink or orange and brown. To English speakers, these pairs of colors, which are objectively no more different from one another than light green and dark green, are conceived of as belonging to different categories. A Russian will make the same red-pink and orange-brown distinctions, but will also make a further distinction between sinii and goluboi, which English speakers would simply call dark and light blue. To Russian speakers, sinii and goluboi are as separate as red and pink or orange and brown.
However, Brent Berlin and Paul Kay, in a classic 1969 study of world wide color naming have argued that these differences can be organized into a coherent hierarchy, and that there are a limited number of universal "basic color terms" which begin to be used by individual cultures in a relatively fixed order. Berlin and Kay based their analysis on a comparison of color words in 20 languages from around the world. To be considered a basic color term, the words had to be monoleximic ("green", but not "light green" or "forest green"), high-frequency, and agreed upon by speakers of that language (this last point, however, can be ambiguous, as native speakers may not always agree with each other). Their analysis showed that, in a culture with only two terms, the two terms would mean roughly 'dark' (covering black, dark colors and cold colors such as blue) and 'bright' (covering white, light colors and warm colors such as red). All languages with three colors terms would add red to this distinction, thus for these languages making three basic color terms. Thus, the three most basic colors are black, white, and red (in his 1924 book Mein Kampf, Adolf Hitler described this as his justification for his choice of the colors for the Nazi flag, as he felt these three colors would most appeal to the masses). These three basic colors appeal to what is today called the reptilian brain. Additional color terms are added in a fixed order as a language evolves: first green and/or yellow (first one, and then the other); then blue; then brown; and finally orange, pink, purple and/or gray, in any order. All languages with six color terms use "black", "white", "red", "green", "blue" and "yellow", which roughly correspond to the sensitivities of the retinal ganglion cells, leading Berlin and Kay to argue that color naming is not merely a cultural phenomenon, but is one that is also constrained by biology, contrary to the Sapir-Whorf hypothesis.
Today every natural language that has words for colors is considered to have from two to twelve basic color terms. All other colors are considered by most speakers of that language to be variants of these basic color terms. English has the eleven basic color terms listed above. Italian and Russian have twelve, distinguishing blue and azure. That doesn't mean English speakers cannot describe the difference of the two colors, of course; however, in English, azure is not a basic color term because one can say light blue instead, while pink is basic because speakers do not say light red.
Color words in a language can also be divided into abstract color words and descriptive color words, though the distinction is blurry in many cases. Abstract color words are words that only refer to a color. In English white, black, red, yellow, green, blue, brown, and gray are definitely abstract color words. These words also happen to be 'basic color terms' in English as described above, but colors like maroon and magenta are also abstract though they may not be considered 'basic color terms' either because they are considered by native speakers to be too rare, too specific, or to be subordinate hues to a higher 'basic color term', in this case red (or maybe purple). Descriptive color words are words that are secondarily used to describe a color but primarily used to refer to an object or phenomenon that has that color. "Salmon", "rose", "saffron", and "lilac" are descriptive color words in English because their use as color words is derived in reference to natural colors of salmon flesh, rose flowers, infusions of saffron pistils, and lilac blossoms respectively. Often a descriptive color word will be a subordinate hyponym of a 'basic color term' (salmon and rose [descriptive] are both hues of pink). In some languages colors may be denoted by descriptive color words even though English may use an abstract color word for the same color; for example in Japanese pink is "momoiro" (桃色, lit. "peach-color") and gray is either "haiiro" or "nezumiiro" (灰色, 鼠色, lit. "ash-color" for light grays and "mouse-color" for dark grays respectively), nevertheless, as languages change they may adopt or invent new abstract color terms, as Japanese has adopted "pinku (ピンク) for pink and "guree" (グレー) for gray from English.
The status of some color words as abstract or descriptive is debatable. The color "pink" was originally a descriptive color word derived from the name of a flower called a "pink" (see dianthus); however, because the word "pink" (flower) has become very rare whereas "pink" (color) has become very common, many native speakers of English use "pink" as an abstract color word alone and furthermore consider it to be one of the 'basic color terms' of English. "purple" is another example of this, as it was originally a word that referred to a dye (see Tyrian purple).
The word "orange" is also difficult to categorize as abstract or descriptive because both its use as a color word and as a word for an object are very common and it is difficult to distinguish which is the primary and which is the secondary use of the word. On the one hand the fruit "orange" has the color "orange," and etymologically the word "orange" as a fruit) from the Sanskrit "narang" or Tamil "naraththai" via the Portuguese "laranja," preceded the use of "orange" as a color word in English. On the other hand "orange" (color) is usually given equal status to red, yellow, green, blue, purple, brown, pink, gray, white and black (all abstract colors) in membership to the 'basic color terms' of English. Based solely on current usages of the word it would be impossible to distinguish if an orange is called an orange because the fruit is orange, or if the color orange is called orange because oranges are orange (other examples of this problem are the colors "violet" and "indigo").
Recently, a researcher at Hewlett-Packard, Nathan Moroney, has been performing an online experiment in unconstrained color naming in English and 21 other languages. He has published some of the results of this work and the experiment is ongoing.
Interestingly, the Hungarian language has two words for "red": piros and vörös, but the difference is too long to explain here. Similarly, the Irish language uses two words for green: glas denotes the green color of plants, while uaithne describes artificial greens of dyes, paints etc. This distinction is made even if two shades are identical.
Some examples of color naming systems are Munsell color system and ISCC-NBS lexicon of color names. The disadvantage of these systems, however, is that they only specify specific color samples, so while it is possible to, by interpolating, convert any color to or from one of these systems, a lookup table is required. In other words, no simple invertible equation can convert between CIE XYZ and one of these systems.
Philatelists traditionally use names to identify postage stamp colors. While the names are largely standardized within each country, there is no broader agreement, and so for instance the US-published Scott catalog will use different names than the British Stanley Gibbons catalogue.
On modern computer systems a standard set of basic color names is now used across the web color names (SVG 1.0/CSS3), HTML color names, X11 color names and the .NET Framework color names, with only a few minor differences.
In fashion and automotive colors the objective of naming is to enhance the perception of color through appropriate naming to fit the emotional context desired. Thus the same "poppy yellow" can become either the hot blooded and active "amber rage", the cozy and peaceful "late afternoon sunshine", or the wealth evoking "sierra gold". Clothiers and clothes marketing often refer to extremely vivid colors as "neon", referencing the bright glow of a neon light.