Breadcrumb Home > Thesaurus > O Synonyms of obsidian Find synonyms for: Noun 1. obsidian, volcanic glass usage: acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of obsidian (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Hanukkah Origins of the Christmas Holiday Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 Krampus: The Christmas Devil Kwanzaa ✖ Related Content Daily Word Quiz: demagogue Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language