夜行
やこう · yakou · JLPT N2 · noun
train
🌙🚆 夜 (night) + 行 (go, travel) = night travel, a train that runs at night
行 means go or travel, as in 旅行 (trip). Put 夜 (night) in front and you get 夜行, travel done after dark.
夜 — 亠 lid + 亻 person + 夕 evening moon
夜 originally depicted a person (亻) under a roof (亠) with the moon (夕) beside them, evoking nighttime rest. The moon component 夕 carries the meaning of evening, while the surrounding elements set the scene of a person at night. Over time it came to mean 'night' in general.
行 — crossroads pictograph (left 彳 + right 亍)
行 originally pictured a four-way crossroads in oracle bone script, with two paths meeting. From 'road' it extended to 'walk, go, travel,' and then to 'a row, line' or 'business firm' (read háng). The two halves 彳 and 亍 are the split sides of that ancient crossroads.