appetiser vs cocktail

appetiser and cocktail both are nouns.

Word	Noun	Adjective	Verb	Adverb
appetiser	Yes	No	No	No
cocktail	Yes	No	No	No

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

appetiser: food or drink to stimulate the appetite (usually served before a meal or as the first course)
cocktail: an appetizer served as a first course at a meal

Other hyponyms of appetiser include antipasto, canape, hors d'oeuvre, crudites.

appetiser (noun)	cocktail (noun)
food or drink to stimulate the appetite (usually served before a meal or as the first course)	a short mixed drink
	an appetizer served as a first course at a meal