A poetic or literary phrase for an evening in spring, often evoking a calm, fleeting atmosphere.
春の夕、桜の花びらが静かに舞い落ちる。
On a spring evening, cherry blossom petals flutter down quietly.
Compound of 春 (spring) + の (possessive particle) + 夕 (evening). The exact origin is uncertain, but it follows a common classical pattern for seasonal expressions.