1.
night train, overnight travel
Travel that takes place during nighttime hours, or a train/bus that operates overnight.
夜行バスに乗る。
To take an overnight bus.
夜行バスで大阪に行った。
I went to Osaka by overnight bus.
夜行列車は安いが疲れる。
Night trains are cheap but tiring.
学生のころはよく夜行バスで旅行していた。
When I was a student, I often traveled by overnight bus.
夜行便は朝早く着くので、時間を有効に使える。
Overnight services arrive early in the morning, so you can use your time effectively.
2.
nocturnal activity
Being active at night, especially referring to animals that are nocturnal.
猫は夜行性だ。
Cats are nocturnal.
夜行性 = nocturnal
フクロウは夜行性の鳥です。
Owls are nocturnal birds.
夜行性の動物は暗い中でも目が見える。
Nocturnal animals can see even in the dark.
ハムスターは夜行性なので、昼間はずっと寝ている。
Hamsters are nocturnal, so they sleep all day.
夜行性の虫は光に集まる習性があるので、夜に窓を開けると入ってくる。
Nocturnal insects have a habit of gathering around light, so they come in when you open the window at night.
夜行 has two main uses: overnight travel (sense 1) and nocturnal behavior (sense 2). It almost always appears as part of a compound rather than standing alone.
COMMON COMPOUNDS (travel):
- 夜行バス: overnight bus
- 夜行列車: night train
- 夜行便: overnight flight/service
COMMON COMPOUNDS (biology):
- 夜行性: nocturnal (adjective for animals)
- 夜行性の動物: nocturnal animal
CONTRAST:
- 夜行 (overnight) vs 日帰り (day trip)
- 夜行 (nocturnal) vs 昼行性 (diurnal)
CULTURE:
夜行バス is a popular budget travel option in Japan, especially among students. Routes connect major cities, departing late at night and arriving early in the morning.