1.
nocturnal; being active at night
The characteristic of being primarily active during the night. Used in biology for animals and sometimes humorously for people who stay up late.
フクロウは夜行性の鳥だ。
Owls are nocturnal birds.
猫はもともと夜行性の動物だ。
Cats are originally nocturnal animals.
夜行性の動物を観察するために、動物園がナイトツアーを開催している。
The zoo holds night tours to observe nocturnal animals.
USAGE:
夜行性 is primarily a biological term but is also used colloquially to describe people who are night owls. It modifies nouns with の.
COMMON COLLOCATIONS:
- 夜行性の動物: nocturnal animal
- 夜行性の生き物: nocturnal creature
CONTRAST:
The opposite is 昼行性 (diurnal — active during the day).
WORD FORMATION:
夜行 (traveling at night) + 性 (nature, characteristic).