noun
first quarter moon; waxing half-moon
Astronomical term for the moon phase when the right half is illuminated in the northern hemisphere. Often contrasted with 下弦 (last quarter).
See also: 下弦
今夜は上弦の月が見える。
Tonight we can see the first quarter moon.
上弦の月は夕方に南の空に見える。
The first quarter moon appears in the southern sky in the evening.