徹夜
てつや · tetsuya · JLPT N3 · noun
night
🌙☕ 徹夜 = pierce through + night: you go through the whole night
徹 means to go all the way through, as in 徹底 (tettei, thorough). Add 夜 (night) and you get a night gone through from start to finish without sleep. 徹夜する = to pull an all-nighter.
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.