/ Thesaurus / S Synonyms of sacral vertebra Find synonyms for: Noun1. sacral vertebra, vertebrausage: one of 5 vertebrae in the human spine that fuse in the adult to form the sacrumWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language