1. An event marking a unique or important historical change of course or one on which important developments depend
   "The invention of the internet was a cusp in human communication";
   - landmark, turning point, watershed
    
2. A sharp point or pointed end; a point where an otherwise smooth curve comes to a point
   "The Gothic arch came to a cusp at its peak"
    
3. Point formed by two intersecting arcs (as from the intrados of a Gothic arch)
   "The architect highlighted the cusps in the cathedral's design";
   - spinode [technical]
    
4. A thin triangular flap of a heart valve
   "The echocardiogram showed a damaged cusp in the mitral valve";
   - leaflet
    
5. Small elevation on the grinding surface of a tooth
   "The molars have several cusps for grinding food"

Derived forms: cusps

Type of: flap, juncture, occasion, peak, point, tip

Part of: cardiac valve, chopper [informal], heart valve, tooth

Encyclopedia: Cusp