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 ).
[ ME -ic, -ik -icus; in many words repr. the cognate Gk -ikos (directly or through L); in some words r. -ique -icus ]