Merlot vs Vitis vinifera

Merlot and Vitis vinifera both are nouns.

Word	Noun	Adjective	Verb	Adverb
Merlot	Yes	No	No	No
Vitis vinifera	Yes	No	No	No

As nouns, Vitis vinifera is a hypernym of Merlot; that is, Vitis vinifera is a word with a broader meaning than Merlot:

Merlot: black wine grape originally from the region of Bordeaux
Vitis vinifera: common European grape cultivated in many varieties; chief source of Old World wine and table grapes

Other hypernyms of Merlot include common grape vine, vinifera, vinifera grape.

Merlot (noun)	Vitis vinifera (noun)
dry red wine made from a grape grown widely in Bordeaux and California	common European grape cultivated in many varieties; chief source of Old World wine and table grapes
black wine grape originally from the region of Bordeaux