any biological cycle that involves periodic changes in blood pressure, body temperature, etc.: analyzed by some to predict behavior, temperament, etc.
An innate, cyclical biological process or function.
- (biology) Any cyclic biological or physiological pattern or activity
- (pseudoscience) Any of three sinusoidal graphs, normally plotted by computer, having a person's birthdate as origin, that that are supposed to give meaningful information about emotional levels, physical energy levels, and mental/psychic sensitivity.
First coined 1960, from bio- + rhythm