Definition of the word cusp

The word "cusp" has its roots in Latin, derived from the word "cuspis," meaning "point" or "tip." In astronomy, a cusp refers to the point where two astronomical bodies, such as the Sun and Moon, seem to meet or touch in the sky. This term was inherited from Old French "cups," which also meant "point" or "tip." Over time, the word "cusp" expanded to describe other points or edges, such as the pointed end of a tooth or the vertex of a leaf. In modern English, the word "cusp" has several meanings, including the astronomical sense, a period of change or transition, and the dental anatomy of a tooth. The word has remained largely unchanged since its Latin roots, and its meaning has evolved to encompass a range of contexts and applications.