first quarter moon; waxing half-moon
Refers to the moon phase when the right half is illuminated, visible in the evening sky. Often contrasted with 下弦の月 (last quarter moon).
See also: 下弦の月
Tonight the first quarter moon looks beautiful.
The waxing half-moon can be seen in the southern sky in the evening.
Compound of 上弦 (first quarter, literally 'upper bowstring') + の (possessive particle) + 月 (moon). The term 上弦 refers to the shape of the moon resembling a bowstring drawn upward.