1Fallen leaves; leaf litter — leaves that have dropped from trees and lie on the ground, typically seen from autumn into winter. Read おちば.
秋になると公園の道は落ち葉で埋まる。
In autumn, the park paths get buried in fallen leaves.
子どもたちは落ち葉の山に飛び込んで遊んだ。
The children jumped into the pile of fallen leaves and played.
毎朝、庭の落ち葉を掃くのが日課だ。
Sweeping up the fallen leaves in the garden every morning is part of my routine.
落ち葉を集めて焚き火をした。
We gathered the fallen leaves and made a bonfire.
2Leaf fall or defoliation — the phenomenon or season of leaves dropping from trees. Read らくよう, used as 落葉する or 落葉が始まる. More formal/written register.
このあたりの木は十一月に落葉する。
The trees around here shed their leaves in November.
今年は暖冬で落葉が遅れている。
Because of the mild winter, leaf fall is late this year.
病気による異常な落葉が見られた。
Abnormal defoliation caused by disease was observed.
3(As 落葉の) deciduous — having the property of shedding leaves in winter, as in 落葉樹 (deciduous tree); contrasts with evergreen in botanical classification. Read らくよう.
落葉樹は冬になると葉をすべて落とす。
Deciduous trees drop all their leaves in winter.
この森は落葉広葉樹が中心で、紅葉が見事だ。
This forest is mainly deciduous broadleaf trees, and the autumn foliage is spectacular.