troy unit vs grain

troy unit and grain both are nouns.

Word	Noun	Adjective	Verb	Adverb
troy unit	Yes	No	No	No
grain	Yes	No	Yes	No

As nouns, grain is a hyponym of troy unit; that is, grain is a word with a more specific, narrower meaning than troy unit:

Other hyponyms of troy unit include pennyweight, apothecaries' ounce, ounce, troy ounce, apothecaries' pound, troy pound.

troy unit (noun)	grain (noun)
any of the unit of the troy system of weights	the direction, texture, or pattern of fibers found in wood or leather or stone or in a woven fabric
	the physical composition of something (especially with respect to the size and shape of the small constituents of a substance)
	the smallest possible unit of anything
	foodstuff prepared from the starchy grains of cereal grasses
	a relatively small granular particle of a substance
	dry seed-like fruit produced by the cereal grasses: e.g. wheat, barley, Indian corn
	a cereal grass
	1/7000 pound; equals a troy grain or 64.799 milligrams
	1/60 dram; equals an avoirdupois grain or 64.799 milligrams
	a weight unit used for pearls or diamonds: 50 mg or 1/4 carat
	the side of leather from which the hair has been removed

troy unit (verb)	grain (verb)
	form into grains
	become granular
	thoroughly work in
	paint (a surface) to make it look like stone or wood