1. a suffix forming adjectives from other parts of speech, occurring originally in Greek and Latin loanwords (metallic; poetic; archaic; public) and, on this model, used as an adjective-forming suffix with the particular senses “having some characteristics of ” (opposed to the simple attributive use of the base noun) (balletic; sophomoric); “in the style of ” (Byronic; Miltonic); “pertaining to a family of peoples or languages” (Finnic; Semitic; Turkic).
2. Chem.a suffix, specialized in opposition to -ous, used to show the higher of two valences: ferric chloride.
3. a noun suffix occurring chiefly in loanwords from Greek, where such words were originally adjectival (critic; magic; music).
—pl. ICs.See immediate constituent.
2. Electronics.integrated circuit.
3. intensive care.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.