/ Thesaurus / P Synonyms of proto Find synonyms for: Adjective1. proto(prenominal), early (vs. middle) (vs. late)usage: indicating the first or earliest or original; "`proto' is a combining form in a word like `protolanguage' that refers to the hypothetical ancestor of another language or group of languages"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language