cusps

noun

• A sharp point or pointed end.
• An important moment when a decision is made that will determine future events.
• 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.
• A point made by the intersection of two curved lines or curved structures, a common motif in Gothic architecture.
• A boundary between zodiacal signs and houses.
• Any of the pointed parts of a canine tooth or molar.
• A flap of a valve of a heart or blood vessel.