Cusp
noun
- a point or pointed end.
- a point where two branches of a curve meet, end, and are tangent.
- decorative device, used especially in Gothic architecture to vary the outlines of intradoses or to form architectural foils, consisting of a pair of curves tangent to the real or imaginary line defining the area decorated and meeting at a point within the area.
- a point of a crescent, especially of the moon. the zodiacal degree that marks the beginning of a house or a sign.
- a point that marks the beginning of a change: