all fours vs seven-up

all fours and seven-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
all fours	Yes	No	No	No
seven-up	Yes	No	No	No

As nouns, seven-up is a hyponym of all fours; that is, seven-up is a word with a more specific, narrower meaning than all fours:

all fours: card games in which points are won for taking the high or low or jack or game
seven-up: a form of all fours in which a total of seven points is game

Other hyponyms of all fours include cinch, auction pitch, pitch, old sledge.

all fours (noun)	seven-up (noun)
card games in which points are won for taking the high or low or jack or game	a form of all fours in which a total of seven points is game