/ Thesaurus / F Synonyms of first law of thermodynamics Find synonyms for: Noun1. conservation of energy, law of conservation of energy, first law of thermodynamics, conservation, law of thermodynamicsusage: the fundamental principle of physics that the total energy of an isolated system is constant despite internal changesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language