highball vs Tom Collins

highball and Tom Collins both are nouns.

Word	Noun	Adjective	Verb	Adverb
highball	Yes	No	No	No
Tom Collins	Yes	No	No	No

As nouns, Tom Collins is a hyponym of highball; that is, Tom Collins is a word with a more specific, narrower meaning than highball:

highball: a mixed drink made of alcoholic liquor mixed with water or a carbonated beverage and served in a tall glass
Tom Collins: tall iced drink of liquor (usually gin) with fruit juice

Other hyponyms of highball include cobbler, collins, gin and tonic, julep, mint julep, Scotch and soda, sling, zombi, zombie.

highball (noun)	Tom Collins (noun)
a mixed drink made of alcoholic liquor mixed with water or a carbonated beverage and served in a tall glass	tall iced drink of liquor (usually gin) with fruit juice