What word or phrase does your mother always say?
"crescent-shaped," early 15c.; "pertaining to the moon," 1620s, from Old French lunaire (15c.), from Latin lunaris "of the moon," from luna "moon," (with capital L- "moon goddess"); see Luna.
lunar lu·nar (lōō'nər)adj.
Relating to the moon or to a month.
Relating to the Moon.
Measured by the revolution of the Moon around the Earth.