寝る
昨日は8時間寝た。
I slept for 8 hours yesterday.
to sleep; to go to bed
疲れたから早く寝る。
I'm tired, so I'll go to bed early.
子供はもう寝ました。
The child has already gone to sleep.
Used for both the act of sleeping and going to bed. Often paired with time expressions (e.g., 8時間寝る 'sleep for 8 hours').
to lie down; to recline
ソファで寝る。
I lie down on the sofa.
Less common than the primary sense of 'sleep'.
(of a plant) to wilt or droop
暑さで花が寝てしまった。
The flowers wilted due to the heat.
Rare usage; primarily literary or poetic.
Related Phrases
Pro Tip
Casual vs. Formal
寝る is casual. For formal situations (e.g., hotels, hospitals), use 就寝する (shūkin suru) or 睡眠する (suimin suru).
Gold Rule
Always pair with time expressions
Japanese often specifies duration or timing when using 寝る. E.g., 8時間寝た (slept for 8 hours), 夜10時に寝る (go to bed at 10 PM).
Word Origin
From Old Japanese *ne- (sleep), related to Proto-Japonic *ne- (sleep). Cognate with Okinawan 寝い (nei) and possibly Korean 자다 (jada).
Usage Notes
寝る is the most common verb for 'to sleep' in casual speech. In formal contexts, 睡眠する (suimin suru) or 就寝する (shūkin suru) may be used. Avoid using 寝る to mean 'to die' (use 亡くなる or 死去する instead).