wedding vs espousal

wedding and espousal both are nouns.

Word	Noun	Adjective	Verb	Adverb
wedding	Yes	No	No	No
espousal	Yes	No	No	No

As nouns, espousal is a hyponym of wedding; that is, espousal is a word with a more specific, narrower meaning than wedding:

Other hyponyms of wedding include bridal, civil marriage, love match, remarriage.

wedding (noun)	espousal (noun)
the act of marrying; the nuptial ceremony	the act of accepting with approval; favorable reception
the social event at which the ceremony of marriage is performed	archaic terms for a wedding or wedding feast
a party of people at a wedding	the act of becoming betrothed or engaged