A rare, literary term for a crescent moon. In everyday Japanese, 三日月 (みかづき) is the standard word. 彎月 may appear in poetry, classical texts, or technical astronomical contexts.
The expression 彎月 can be found in old waka poetry.
In astronomical literature, the term 彎月 is sometimes used.
crescent shape
From Chinese 彎月 (wānyuè), literally 'curved moon'. The kanji 彎 means 'curve' or 'bend', and 月 means 'moon'. The reading is on'yomi.