long horse vs vaulting horse

long horse and vaulting horse both are nouns.

Word	Noun	Adjective	Verb	Adverb
long horse	Yes	No	No	No
vaulting horse	Yes	No	No	No

As nouns, long horse and vaulting horse are synonyms defined as:

long horse and vaulting horse: a gymnastic horse without pommels and with one end elongated; used lengthwise for vaulting

Other synonyms of long horse include buck.

long horse (noun)	vaulting horse (noun)
a gymnastic horse without pommels and with one end elongated; used lengthwise for vaulting	a gymnastic horse without pommels and with one end elongated; used lengthwise for vaulting