1a pointed end where two curves meet, in particular:
Architecture a moulded projection at the point of a small arch in Gothic tracery.
a cone-shaped prominence on the surface of a tooth.
Anatomy a pocket or fold in the wall of the heart or a major blood vessel that fills and distends if the blood flows backwards, so forming part of a valve.
Mathematics a point at which the direction of a curve is abruptly reversed.
each of the pointed ends of the crescent moon.
Botany a sharp rigid point of a leaf.
2 Astrology the initial point of an astrological sign or house:he was Aries on the cusp with Taurus
3a point of transition between two different states:those on the cusp of adulthood
