nightdress vs lingerie

nightdress and lingerie both are nouns.

Word	Noun	Adjective	Verb	Adverb
nightdress	Yes	No	No	No
lingerie	Yes	No	No	No

As nouns, lingerie is a hypernym of nightdress; that is, lingerie is a word with a broader meaning than nightdress:

nightdress: lingerie consisting of a loose dress designed to be worn in bed by women
lingerie: women's underwear and nightclothes

Other hypernyms of nightdress include intimate apparel, nightclothes, nightwear, sleepwear.

nightdress (noun)	lingerie (noun)
lingerie consisting of a loose dress designed to be worn in bed by women	women's underwear and nightclothes