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[bahy-oh-rith-uh m] /ˈbaɪ oʊˌrɪð əm/
Physiology. an innate periodicity in an organism's physiological processes, as sleep and wake cycles.
Origin of biorhythm
1960-65; bio- + rhythm
Related forms
biorhythmic, adjective
[bahy-oh-rith-mis-i-tee] /ˌbaɪ oʊ rɪðˈmɪs ɪ ti/ (Show IPA),
biorhythmist, biorhythmicist, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for biorhythm
  • According to the biorhythm theory, the positive period of these cycles would be the best times for record athletic performance.
British Dictionary definitions for biorhythm


a cyclically recurring pattern of physiological states in an organism or organ, such as alpha rhythm or circadian rhythm; believed by some to affect physical and mental states and behaviour
Derived Forms
biorhythmic, adjective
biorhythmically, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for biorhythm

also bio-rhythm, 1960, from bio- + rhythm. Related: Biorhythmic.

Online Etymology Dictionary, © 2010 Douglas Harper
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biorhythm in Medicine

biorhythm bi·o·rhythm (bī'ō-rĭð'əm)
A biologically inherent cyclic variation or recurrence of an event or state, such as sleep cycles, circadian rhythms, and periodic diseases.

bi'o·rhyth'mic (-rĭð'mĭk) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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biorhythm in Science
A recurring biological process, such as sleep, that is controlled by the circadian rhythms of an organism. See more at circadian rhythm.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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