wedding vs wedding party

wedding and wedding party both are nouns.

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

As nouns, wedding and wedding party are synonyms defined as:

wedding (noun)	wedding party (noun)
the act of marrying; the nuptial ceremony	a party of people at a wedding
the social event at which the ceremony of marriage is performed
a party of people at a wedding