1. The time at which the Moon is at first or last quarter when half its face is illuminated
   "Astronomers observed the half-moon through their telescopes"
    
2. The crescent-shaped area at the base of the human fingernail
   "The half-moon is often more visible on the thumb than on other fingers";
   - lunula, lunule

Derived forms: half-moons

Type of: area, phase of the moon, region

Part of: month, nail

Encyclopedia: Half-moon