Nightwear is the clothes you put on for bed. That can be pyjamas (a soft top and trousers), a nightdress or nightgown (a long loose dress), and sometimes a robe you pull on if you get up in the dark. Shops use nightwear as a group name for that whole shelf. At home, though actually, many families just say pyjamas for all of it, even when someone is wearing a nightdress. You wear it to sleep, not to school or to the shops — unless you are joking. It is an everyday, slightly tidy word: more like a label on a packet than a word people shout. Sleepwear means the same thing.

睡衣類（睡衣、睡裙、睡袍等）