One of the mysteries of the English language finally explained.
With singular concord. The biorhythmic properties of a person or other living organism; the study of biorhythms, specifically the use of one's own biorhythms for the purposes of self-improvement.
1940s; earliest use found in Acta Psychiatrica et Neurologica Supplementum. From biorhythmic: see -ic.
In this article we explore how to impress employers with a spot-on CV.