Color

Color (or colour in Commonwealth English; see spelling differences) is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, emission, reflection and transmission. For most humans, visible wavelengths of light are the ones perceived in the visible light spectrum, with three types of cone cells (trichromacy). https://en.wikipedia.org/wiki/Color

a design element/attribute

Colour Coding Language - PDF

Color coding is widely used to support literacy, language and organisation; however, it is not limited to these areas.

Color coded writing is an adjustment to text that supports verbal expression, reading comprehension and writing development. Color coded writing provides an additional layer of meaning to text that visually supports students with literacy difficulties, Language Disorder and/or executive functioning weaknesses to identify grammatical elements of our language system.