noun
prose poem
A literary work that uses prose form but has poetic qualities such as heightened imagery and emotional effect.
ボードレールの『パリの憂鬱』は有名な散文詩集だ。
Baudelaire's 'Paris Spleen' is a famous collection of prose poems.
散文 means prose in general, without the poetic qualities that define 散文詩.
Compound of 散文 (prose) and 詩 (poem). The term is a calque from Western literary criticism, entering Japanese in the modern era.