biorhythm
/ˈbaɪoʊˌrɪðəm/
noun
- A regular, repeating pattern of physical, emotional, or mental changes in a living thing, often believed to follow a fixed cycle.
- The app claims to track your daily biorhythm based on your birth date.
- Some people think their biorhythm affects how energetic they feel.
- She checked her biorhythm chart to see if it was a good day for a test.