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'.
I want to lie down for a bit.
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.
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.
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'.
He is lying on the sofa.
The cat is lying in the sun.
Emphasizes the horizontal state, often used when someone is resting but not necessarily sleeping.
She is lying down on the bed.
Describes lounging or sprawling out lazily. More casual than 寝ている.
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.
A tree is lying across the road.
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.
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.
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.
I couldn't sleep well last night.
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.