What is the name given to the moon phase when three-quarters of the moon is visible?

The term used to describe the moon phase when three-quarters of the moon is visible is "gibbous moon." In this phase, more than half but not fully illuminated, the moon appears more rounded than a half moon but less than a full moon. This is in contrast to other phases; for example, a full moon occurs when the entire face of the moon is illuminated, and a half moon—also known as the first or last quarter—refers to when exactly half of the moon is visible. A crescent moon, on the other hand, is when significantly less than half of the moon is illuminated. Thus, the gibbous moon correctly identifies the phase being described, where three-quarters of the moon is observable.