/ Thesaurus / P Synonyms of phanerozoic aeon Find synonyms for: Noun1. Phanerozoic, Phanerozoic eon, Phanerozoic aeonusage: the period from about 5,400 million years ago until the presentWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language