tights vs pantyhose

tights and pantyhose both are nouns.

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

As nouns, pantyhose is a hyponym of tights; that is, pantyhose is a word with a more specific, narrower 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
pantyhose: a woman's tights consisting of underpants and stockings

Other hyponyms of tights include maillot.

tights (noun)	pantyhose (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	a woman's tights consisting of underpants and stockings