/ Thesaurus / A Synonyms of ammonia clock Find synonyms for: Noun1. ammonia clock, atomic clockusage: an atomic clock based on vibrational frequency of the nitrogen atom in the ammonia moleculeWordNet 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