Definition of cusps:
(n) :
(figuratively) An important moment when a decision is made that will determine future events.
(n) :
(astrology) A boundary between zodiacal signs and houses.
(n) :
A sharp point or pointed end.
(n) :
A point of transition.
(n) :
(geometry) A point of a curve where the curve is continuous but has no derivative, but such that it has a derivative at every nearby point.
(n) :
(architecture) A point made by the intersection of two curved lines or curved structures, a common motif in Gothic architecture.