Translation guide
Clothing worn for sleeping. In Japanese, the most common term is パジャマ (pajama), a loanword from English. Traditional Japanese sleepwear like 寝巻き (nemaki) and 浴衣 (yukata) are also used, but パジャマ is the default in modern daily life.
Clothes worn to bed, typically a set of a top and bottom.
The most common and neutral word for pajamas or nightclothes. Used for Western-style sleepwear.
新しいパジャマを買った。
I bought new nightclothes.
パジャマに着替える。
I change into my pajamas.
Traditional Japanese nightclothes, often a kimono-style robe. Less common in modern daily use but still understood.
祖母は寝巻きを着ている。
My grandmother wears a nightgown.
Loanword from English 'nightwear'. Used in fashion or retail contexts, but not common in daily conversation.
デパートでナイトウェアを探す。
I look for nightwear at the department store.
A one-piece garment worn for sleeping, typically for women.
A loanword from French 'négligé', used for a women's nightgown or sleep dress. Common in Japanese.
彼女はネグリジェを着て寝ている。
She sleeps in a nightgown.
Literal translation of 'sleep dress', used in some fashion contexts but not common.
スリープドレスはあまり一般的ではない。
Sleep dresses are not very common.
A casual cotton kimono often worn after bathing or as sleepwear, especially in ryokan.
A light cotton kimono used as sleepwear or loungewear, especially at Japanese inns or during summer festivals. Not exclusively nightclothes but commonly used as such.
旅館で浴衣に着替えた。
I changed into a yukata at the ryokan.
In modern Japanese, パジャマ covers most types of nightclothes. Use it unless you specifically mean a traditional garment or a nightgown.