poetry composed on a set theme
Refers to a poem, typically waka or haiku, written on a given topic rather than from spontaneous inspiration. Common in traditional Japanese poetry gatherings.
At poetry gatherings, participants often compose poems on assigned themes.
This poem on a set theme takes 'the moon' as its topic.
Compound of 題 (theme, topic) and 詠 (compose poetry). The exact historical derivation is uncertain, but the term is conventionally associated with traditional Japanese poetic practice.