and gradually increases from a waxing "crescent" (for its shape into the first quarter moon. As it continues to brighten, it takes on an oblong, or "gibbous," shape until it reaches the full moon ...
waxing gibbous, Full Moon, waning gibbous, Last Quarter, and waning crescent. A cycle starting from one Full Moon to its next counterpart, termed the synodic month or lunar month, lasts about 29.5 ...