/ Dictionary / Index P proto-Ionic: Meaning and Definition of Find definitions for: pro•to-I•on•ic Pronunciation: (prō"tō-ī-on'ik), [key] — adj. of or pertaining to architecture supposedly anticipating the Grecian Ionic order. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Proto-Indo-European protolanguage Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language