/ Dictionary / Index T thermos: Meaning and Definition of Find definitions for: ther•mos Pronunciation: (thûr'mus), [key] — n. a vacuum bottle or similar container lined with an insulating material, such as polystyrene, to keep liquids hot or cold. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thermos (Thesaurus) thermoregulation thermosensitive Related Content Daily Word Quiz: wizened Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language