-ic

  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. Chemistry. 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).

Origin of -ic

Middle English -ic, -ik < Latin -icus; in many words representing the cognate Greek -ikos (directly or through L); in some words replacing -ique < French < Latin -icus
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for -ic

-ic

suffix forming adjectives
  1. of, relating to, or resemblingallergic; Germanic; periodic See also -ical
  2. (in chemistry) indicating that an element is chemically combined in the higher of two possible valence statesferric; stannic Compare -ous (def. 2)

Word Origin for -ic

from Latin -icus or Greek -ikos; -ic also occurs in nouns that represent a substantive use of adjectives (magic) and in nouns borrowed directly from Latin or Greek (critic, music)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for -ic

adjective suffix, "having to do with, having the nature of, being, made of, caused by, similar to" (in chemistry, indicating a higher valence than names in -ous), from French -ique and directly from Latin -icus, which in many cases represents Greek -ikos "in the manner of; pertaining to." From PIE *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames.

Online Etymology Dictionary, © 2010 Douglas Harper

-ic in Medicine

-ic

suff.
  1. Of, relating to, or characterized by:carbonic.
  2. Having a valence higher than that of a specified element in compounds or ions named with adjectives ending in -ous:ferric.
  3. Of or relating to an acid:sulfuric acid.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.