mid-13c., peinten, "represent (someone or something) in paint;" c. 1300, "decorate (something or someone) with drawings or pictures;" early 14c., "put color or stain on the surface of; coat or cover with a color or colors;" from Old French peintier "to paint," from peint, past participle of peindre "to paint," from Latin pingere "to paint, represent in a picture, stain; embroider, tattoo," from a nasalized form of PIE root *peig- "to cut, mark by incision."
The sense evolution between PIE and Latin was, presumably, "decorate with cut marks" to "decorate" to "decorate with color." Compare Sanskrit pingah "reddish," pesalah "adorned, decorated, lovely;" Old Church Slavonic pegu "variegated;" Greek poikilos "variegated;" Old High German fehjan "to adorn;" Old Church Slavonic pisati, Lithuanian piešiu, piešti "to write." Probably also representing the "cutting" branch of the family is Old English feol (see file (n.2)).
From late 14c. as "represent persons and things in pictures or drawing, portray." To paint the town (red) "go on a boisterous or disorderly spree" is by 1884; to paint (someone or something) black "represent it as wicked or evil" is from 1590s. Adjective paint-by-numbers "simple" is attested by 1970; the art-for-beginners kits themselves date to c. 1953.
late 13c. (in compounds), "that with which something is painted, a substance used in painting," from paint (v.) or from the derived noun in Old French. Of rouge, make-up, etc., from 1650s. Paint-brush "brush for applying paints" is attested from 1827. Paint-box "box with compartments for holding different paints" is by 1725.
It differs from a dye in that it is not designed to sink into the substance to which it is applied, but to form a superficial coating. The term pigment is sometimes restricted to the dry coloring material of which a paint is made. [Century Dictionary]