/ Dictionary / Index T tonus: Meaning and Definition of Find definitions for: to•nus Pronunciation: (tō'nus), [key] — n. Physiol. a normal state of continuous slight tension in muscle tissue that facilitates its response to stimulation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: tonus (Thesaurus) tontine tony Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language