From Longman Dictionary of Contemporary Englishbiorhythmsbi‧o‧rhyth‧ms /ˈbaɪəʊˌrɪðəmz $ ˈbaɪoʊ-/ noun [plural] HBHregular changes in the speed at which physical processes happen in your body, which some people believe can affect the way you feel
Examples from the Corpus
biorhythms• Arthur Schlesinger keeps writing about cycles of history, while New Age psychotherapists rhapsodize about biorhythms.• The biorhythms program is simple and easy to use for those who know the subject but are not computer boffins.• It had more to do with biorhythms or the moon or something. 