martingale vs stable gear

martingale and stable gear both are nouns.

Word	Noun	Adjective	Verb	Adverb
martingale	Yes	No	No	No
stable gear	Yes	No	No	No

As nouns, stable gear is a hypernym of martingale; that is, stable gear is a word with a broader meaning than martingale:

martingale: a harness strap that connects the nose piece to the girth; prevents the horse from throwing back its head
stable gear: gear for a horse

Other hypernyms of martingale include saddlery, tack.

martingale (noun)	stable gear (noun)
a harness strap that connects the nose piece to the girth; prevents the horse from throwing back its head	gear for a horse
spar under the bowsprit of a sailboat