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