n.

1. 秋季，秋天[C][U]
   American people use the word "fall" to mean autumn.

   美國人用"fall"這個字來表示秋天。

2. 成熟期；漸衰期；凋落期[U]

a.

1. 秋天的，秋季的[B]

n.

1. chiefly Brit. the season after summer and before winter.
2. Astronomy  the period from the autumn equinox to the winter solstice.