marriage vs wedlock

marriage and wedlock both are nouns.

Word	Noun	Adjective	Verb	Adverb
marriage	Yes	No	No	No
wedlock	Yes	No	No	No

As nouns, marriage and wedlock are synonyms defined as:

marriage and wedlock: the state of being a married couple voluntarily joined for life (or until divorce)

Other synonyms of marriage include matrimony, spousal relationship, union.

marriage (noun)	wedlock (noun)
the act of marrying; the nuptial ceremony	the state of being a married couple voluntarily joined for life (or until divorce)
two people who are married to each other
the state of being a married couple voluntarily joined for life (or until divorce)
a close and intimate union