A color term, also known as a color name, is a word or phrase that refers to a specific color. The color term may refer to human perception of that color (which is affected by visual context) which is usually defined according to the Munsell color system, or to an underlying physical property (such as a specific wavelength of visible light). There are also numerical systems of color specification, referred to as color spaces. An important distinction must be established between color and shape, these two attributes usually are used in conjunction with one another when describing in language. For example, being labeled as alternative parts of speech terms color term and shape term. Psychological conditions for recognition of colors exist. Such as those who cannot discern colors in general (Aphantasia) or those who see colors as sound (Synesthesia)
color words are composed of individual lexemes, or root words, 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 (shades of red, orange, yellow, green, blue, and purple), 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.