-ic

suffix

Etymology: From Middle English -ik, from Old French -ique, from Latin -icus, from Proto-Indo-European *-kos, *-ḱos, formed with the i-stem suffix *-i- and the adjectival suffix *-kos, *-ḱos. Compare Ancient Greek -ικός (-ikós), Sanskrit -इक (-ika) and Old Church Slavonic -ъкъ (-ŭkŭ). Doublet of -y; compare also -ac. Proto-Indo-European *-kos on noun stems carried the meaning 'characteristic of, like, typical, pertaining to', and on adjectival stems it acted emphatically.

1. Used to form adjectives from nouns with the meaning “of or pertaining to”.

   “Cyril + -ic → Cyrillic”

   “acid + -ic → acidic”

2. Used to denote certain chemical compounds in which a specified chemical element has a higher oxidation number than in the equivalent compound whose name ends in the suffix -ous. For example sulphuric acid (H₂SO₄) has more oxygen atoms per molecule than sulphurous acid (H₂SO₃).