erotism vs sexual desire

erotism and sexual desire both are nouns.

Word	Noun	Adjective	Verb	Adverb
erotism	Yes	No	No	No
sexual desire	Yes	No	No	No

As nouns, sexual desire is a hypernym of erotism; that is, sexual desire is a word with a broader meaning than erotism:

Other hypernyms of erotism include concupiscence, eros, physical attraction.

erotism (noun)	sexual desire (noun)
the arousal of feelings of sexual desire	a desire for sexual intimacy
a state of anticipation of sexuality