/ Dictionary / Index B biorhythm: Meaning and Definition of Find definitions for: bi•o•rhythm Pronunciation: (bī'ō-ri"um), [key] — n. an innate periodicity in an organism's physiological processes, as sleep and wake cycles. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bioresearch biorhythmics Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language