From Sino-Japanese 時間: 時 (ji, "time/hour", from Old Chinese 時 shí) + 間 (kan, "interval/between", from Old Chinese 間 jiān). The compound entered Japanese through classical Chinese texts and became ubiquitous in modern Japanese for both abstract "time" and concrete "duration."

Japanese culture places enormous value on punctuality, and 時間 sits at the heart of that. Phrases like 時間を守る (jikan o mamoru, "to keep time / be on time") are social expectations, not mere suggestions. Being late is considered disrespectful — trains apologize over the intercom even for a one-minute delay. Note that 時間 can mean both "time" in general and a specific hour (e.g., 何時間? = "how many hours?"), while 時刻 (jikoku) is used for an exact clock time on timetables — a subtle distinction worth knowing.