形容词

1. 夜间发生的;夜间的
Nocturnal means occurring at night.

2. (动物)夜间活动的，夜行性的
Nocturnal creatures are active mainly at night.

1. belonging to or active during the night

e.g. nocturnal animals are active at night
nocturnal plants have flowers that open at night and close by day

2. of or relating to or occurring in the night

e.g. nocturnal darkness