tights vs hosiery

tights and hosiery both are nouns.

Word	Noun	Adjective	Verb	Adverb
tights	Yes	No	No	No
hosiery	Yes	No	No	No

As nouns, hosiery is a hypernym of tights; that is, hosiery is a word with a broader meaning than tights:

tights: skintight knit hose covering the body from the waist to the feet worn by acrobats and dancers and as stockings by women and girls
hosiery: socks and stockings and tights collectively (the British include underwear)

Other hypernyms of tights include hose.

tights (noun)	hosiery (noun)
skintight knit hose covering the body from the waist to the feet worn by acrobats and dancers and as stockings by women and girls	socks and stockings and tights collectively (the British include underwear)