troy grain
nounEtymology Morphologically, from Troyes, town in Northern France + grain, unit of mass.
1
A unit of mass, equal to 1/24 of a pennyweight or 1/480 of a troy ounce, fixed at 0.064 798 91 grams under the metric system.
Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.