merchandise vs product

merchandise and product both are nouns.

Word	Noun	Adjective	Verb	Adverb
merchandise	Yes	No	Yes	No
product	Yes	No	No	No

As nouns, merchandise and product are synonyms defined as:

Other synonyms of merchandise include ware.

As nouns, product is a hypernym of merchandise; that is, product is a word with a broader meaning than merchandise:

merchandise: branded products meant to promote another product, especially films and pop groups
product: items for sale to the individual consumer

Other hypernyms of merchandise include merchandise, ware.

merchandise (noun)	product (noun)
items for sale to the individual consumer	an artifact that has been created by someone or some process
branded products meant to promote another product, especially films and pop groups	items for sale to the individual consumer
	a quantity obtained by multiplication
	the set of elements common to two or more sets
	a consequence of someone's efforts or of a particular set of circumstances
	a chemical substance formed as a result of a chemical reaction

merchandise (verb)	product (verb)
engage in the trade of