hostler vs ostler

hostler and ostler both are nouns.

Word	Noun	Adjective	Verb	Adverb
hostler	Yes	No	No	No
ostler	Yes	No	No	No

As nouns, hostler and ostler are synonyms defined as:

hostler and ostler: someone employed in a stable to take care of the horses

Other synonyms of hostler include groom, stableboy, stableman.

hostler (noun)	ostler (noun)
someone employed in a stable to take care of the horses	someone employed in a stable to take care of the horses