troy ounce vs ounce

troy ounce and ounce both are nouns.

Word	Noun	Adjective	Verb	Adverb
troy ounce	Yes	No	No	No
ounce	Yes	No	No	No

As nouns, troy ounce and ounce are synonyms defined as:

troy ounce and ounce: a unit of apothecary weight equal to 480 grains or one twelfth of a troy pound

Other synonyms of troy ounce include apothecaries' ounce.

troy ounce (noun)	ounce (noun)
a unit of apothecary weight equal to 480 grains or one twelfth of a troy pound	large feline of upland central Asia having long thick whitish fur
	a unit of weight equal to one sixteenth of a pound or 16 drams or 28.349 grams
	a unit of apothecary weight equal to 480 grains or one twelfth of a troy pound