isochromatic adj.

before vowels often is-, word-forming element meaning "equal, similar, identical; isometric," from Greek isos "equal to, the same as; equally divided; fair, impartial (of persons); even, level (of ground)," as in isometor "like one's mother." In English used properly only with words of Greek origin; the Latin equivalent is equi- (see equi-).

in reference to color, "intensity of distinctive hue, degree of departure of a color-sensation from that of white or gray," 1889, from Latinized form of Greek khrōma "surface of the body, skin, color of the skin," also used generically for "color" and, in plural, "ornaments, makeup, embellishments," a verbal noun from khroizein "to color, stain, to touch the surface of the body," khrosthenai "to take on a color or hue," from khros, khroia "surface of the body, skin."

Beekes considers this noun to be of uncertain origin. It sometimes is explained as being somehow from PIE *ghreu- "to rub, grind" (see grit (n.)).

Middle English -ik, -ick, word-forming element making adjectives, "having to do with, having the nature of, being, made of, caused by, similar to," from French -ique and directly from Latin -icus or from cognate Greek -ikos "in the manner of; pertaining to." From PIE adjective suffix *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames. In chemistry, indicating a higher valence than names in -ous (first in benzoic, 1791).

In Middle English and after often spelled -ick, -ike, -ique. Variant forms in -ick (critick, ethick) were common in early Modern English and survived in English dictionaries into early 19c. This spelling was supported by Johnson but opposed by Webster, who prevailed.