Merlot vs common grape vine

Merlot and common grape vine both are nouns.

Word	Noun	Adjective	Verb	Adverb
Merlot	Yes	No	No	No
common grape vine	Yes	No	No	No

As nouns, common grape vine is a hypernym of Merlot; that is, common grape vine is a word with a broader meaning than Merlot:

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

Other hypernyms of Merlot include vinifera, vinifera grape, Vitis vinifera.

Merlot (noun)	common grape vine (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