Quarter moons are a fascinating celestial sight that can be observed in the night sky. Also known as half-moons, they represent a phase in the lunar cycle when exactly half of the moon is illuminated by the sun. There are several synonyms for "quarter moons," including waxing gibbous, waning gibbous, first quarter, and last quarter. Waxing gibbous refers to a moon that appears to be progressively increasing in size from a half-moon, while waning gibbous describes a moon that is shrinking in size from a full moon. The first quarter and last quarter describe the specific times at which the moon is one-quarter illuminated. These varying phases of the moon add to the beauty and mystery of the night sky.