cookout vs barbecue

cookout and barbecue both are nouns.

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

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

cookout: an informal meal cooked and eaten outdoors
barbecue: a cookout in which food is cooked over an open fire; especially a whole animal carcass roasted on a spit

Other hyponyms of cookout include barbeque, clambake, fish fry, weenie roast, wiener roast, burgoo.

cookout (noun)	barbecue (noun)
an informal meal cooked and eaten outdoors	a rack to hold meat for cooking over hot charcoal usually out of doors
	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

cookout (verb)	barbecue (verb)
	cook outdoors on a barbecue grill