horse vs buck

horse and buck both are nouns.

Word	Noun	Adjective	Verb	Adverb
horse	Yes	No	Yes	No
buck	Yes	No	Yes	No

As nouns, horse and buck are synonyms defined as:

Other synonyms of horse include sawbuck, sawhorse.

As nouns, buck is a hyponym of horse; that is, buck is a word with a more specific, narrower meaning than horse:

horse: a padded gymnastic apparatus on legs
buck: a gymnastic horse without pommels and with one end elongated; used lengthwise for vaulting

Other hyponyms of horse include pommel horse, side horse, long horse, vaulting horse.

horse (noun)	buck (noun)
solid-hoofed herbivorous quadruped domesticated since prehistoric times	mature male of various mammals (especially deer or antelope)
a chessman shaped to resemble the head of a horse; can move two squares horizontally and one vertically (or vice versa)	a framework for holding wood that is being sawed
a framework for holding wood that is being sawed	a gymnastic horse without pommels and with one end elongated; used lengthwise for vaulting
a padded gymnastic apparatus on legs	a piece of paper money worth one dollar
troops trained to fight on horseback

horse (verb)	buck (verb)
provide with a horse or horses	jump vertically, with legs stiff and back arched
	move quickly and violently
	resist
	to strive with determination