/ Thesaurus / L Synonyms of lower mantle Find synonyms for: Noun1. lower mantle, layerusage: the deeper part of the mantleWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language