grill vs barbecue

grill and barbecue both are nouns.

Word	Noun	Adjective	Verb	Adverb
grill	Yes	No	Yes	No
barbecue	Yes	No	Yes	No

As verbs, barbecue is a hyponym of grill; that is, barbecue is a word with a more specific, narrower meaning than grill:

Other hyponyms of grill include barbeque, cook out, hibachi, broil, oven broil.

grill (noun)	barbecue (noun)
a framework of metal bars used as a partition or a grate	a rack to hold meat for cooking over hot charcoal usually out of doors
a restaurant where food is cooked on a grill	a cookout in which food is cooked over an open fire; especially a whole animal carcass roasted on a spit
	meat that has been barbecued or grilled in a highly seasoned sauce

grill (verb)	barbecue (verb)
cook over or under a grill	cook outdoors on a barbecue grill
examine thoroughly