深夜
しんや · shinya · JLPT N2 · noun
night
🌙 深 (deep) + 夜 (night) = deep night, meaning late at night
深 (shin) means deep and 夜 (ya) means night, so the compound is deep night: the hours well past dusk when most people are asleep. The same 深 appears in 深海 (shinkai), deep sea.
深 — water radical 氵 + 罙 (phonetic, depth)
深 combines the water radical 氵 with 罙, which depicts a hand reaching into a cave or hollow. Originally it described deep water, then broadened to mean 'deep' in any sense — distance, color, or feeling. The 氵 gives the meaning, while 罙 hints at both sound and the idea of reaching far in.
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.