/ Dictionary / Index P Proto-Indo-European: Meaning and Definition of Find definitions for: Pro•to-In•do-Eu•ro•pe•an Pronunciation: (prō'tō-in"dō-yoor"u-pē'un), [key] — n. the unattested prehistoric parent language of the Indo-European languages; Indo-European. —adj. of or pertaining to Proto-Indo-European. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. protohuman proto-Ionic 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