From Longman Dictionary of Contemporary Englishnightienight‧ie /ˈnaɪti/ noun [countable] informal DCCa nightdress
Examples from the Corpus
nightie• He felt her nightie brush his ear.• She slipped into her nightie and slid into bed beside Tom, who was asleep and breathing through his mouth.• Carrie sat cross-legged beside me, her tummy huge under her nightie.• After he had gone I found that my nightie was covered in a horrible sticky mess with a strange sour smell.• Could you picture Fat Pat in her red nightie and fishnets and keep your tea down?• Something big was going to happen and it wasn't going to start in Olivia's nightie.• The nighties went on sale this afternoon.• Maybe you have to throw a coat over your nightie and pick them up from miles away in the car. 