Definition

1. Noun:
   • A lunar phase: "half-moon" refers to the time when the Moon appears as a semicircle, with exactly half of its visible face illuminated by the Sun. This occurs at the first quarter and last quarter phases of the Moon's cycle.
   • A fingernail feature: "half-moon" also refers to the pale, whitish, crescent-shaped area at the base of a human fingernail or toenail.

Usage Examples

• Noun (Lunar Phase):
  • We went for a walk under the bright half-moon.
  • The calendar marks the next half-moon for next Tuesday.
• Noun (Fingernail Feature):
  • The doctor checked the color of the half-moons on her fingernails.
  • A healthy half-moon is usually visible on the thumbnail.

Advanced Usage

• "a half-moon shape": describing any object or form that resembles a crescent or a semicircle.
  • The patio was designed in a half-moon shape.

Variants and Related Words

• Lunula (n): The technical, anatomical term for the whitish area at the base of a nail.
• Crescent (n): A shape resembling the curved sickle shape of the waxing or waning moon, often used interchangeably in general contexts, though a true half-moon is a semicircle, not a thin crescent.

Synonyms

• First quarter moon: Specifically for the half-moon phase after the new moon.
• Last quarter moon: Specifically for the half-moon phase before the new moon.

Related Idioms

• (No common idioms use "half-moon" as a standalone term. It is typically used literally.)

Noun

1. the time at which the Moon is at first or last quarter when half its face is illuminated
2. the crescent-shaped area at the base of the human fingernail