A lot vs. Alot: 9 Grammatical Pitfalls
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.
A recurring biological process, such as sleep, that is controlled by the circadian rhythms of an organism. See more at circadian rhythm.