As nouns the difference between nightgown and sleepwear
is that nightgown is a garment mainly worn by women for sleeping in while sleepwear is garments designed to be worn in bed; nightclothes.
nightgown
English
Noun
(
en noun)
A garment mainly worn by women for sleeping in.
See also
*
sleepwear
English
Noun
(-)
garments designed to be worn in bed; nightclothes