all fours vs old sledge

all fours and old sledge both are nouns.

Word	Noun	Adjective	Verb	Adverb
all fours	Yes	No	No	No
old sledge	Yes	No	No	No

As nouns, old sledge is a hyponym of all fours; that is, old sledge 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
old sledge: a form of all fours in which a total of seven points is game

Other hyponyms of all fours include cinch, auction pitch, pitch, seven-up.

all fours (noun)	old sledge (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