Translation guide
Describes the state or action of being in a horizontal position, typically on a surface like a bed or floor. Japanese uses different verbs for the action of lying down versus the state of lying down, and the choice depends on whether the subject is animate or inanimate.
To express the action of a person or animal moving into a lying position.
The most common and natural way to say 'lie down' for people. It literally means 'become horizontal'.
ちょっと横になりたい。
I want to lie down for a bit.
疲れたから、少し横になろう。
I'm tired, so let's lie down for a while.
Means to lie down casually or sprawl out, often on the floor or a sofa. Implies a relaxed, informal posture.
子供たちが芝生に寝転んでいる。
The kids are lying down on the lawn.
To lie face down, often to hide or take cover. Can also mean to cast one's eyes down.
兵士たちは地面に伏せた。
The soldiers lay down on the ground (face down).
To describe a person or animal already in a lying position.
The most common way to say 'is lying down' for people. It can also mean 'is sleeping', but context usually clarifies. Literally 'is lying'.
彼はソファに寝ている。
He is lying on the sofa.
猫が日向で寝ている。
The cat is lying in the sun.
Emphasizes the horizontal state, often used when someone is resting but not necessarily sleeping.
彼女はベッドで横になっている。
She is lying down on the bed.
Describes lounging or sprawling out lazily. More casual than 寝ている.
休みの日は一日中寝そべっている。
On my day off, I lie around all day.
To describe an object that is in a horizontal or flat position.
Used for objects that have fallen over and are lying on their side. Implies the object was originally upright.
木が道に倒れている。
A tree is lying across the road.
本棚が倒れている。
The bookshelf is lying on its side.
Means 'is placed' and can describe something lying flat if it was intentionally put there. Not specifically 'lying down' but often used for objects on surfaces.
机の上に本が置いてある。
A book is lying on the desk.
Specifically means something has been laid down on its side intentionally. Often used for bottles or long objects.
ワインは寝かせて保存する。
Wine is stored lying down.
寝る (neru) primarily means 'to sleep' or 'to lie down (to sleep)'. 横になる (yoko ni naru) focuses on the action of assuming a horizontal position, often for rest. If you say 寝たい (I want to sleep), it implies you want to go to bed. If you say 横になりたい, it means you want to lie down, perhaps just to rest your back.
昨夜よく寝られなかった。
I couldn't sleep well last night.
頭が痛いので、少し横になります。
I have a headache, so I'll lie down for a bit.
寝る (neru) is only for living things. For objects lying down, use 倒れている (taorete iru) if fallen over, or 置いてある (oite aru) if placed.