a system of weights in use for precious metals and gems (formerly also for bread, grain, etc.): 24 grains = 1 pennyweight (1.555 grams); 20 pennyweights = 1 ounce (31.103 grams); 12 ounces = 1 pound (0.373 kilogram). The grain, ounce, and pound are the same as in apothecaries' weight, the grain alone being the same as in avoirdupois weight. The troy pound is no longer a standard weight in Great Britain.
Origin of troy weight
late Middle English word dating back to 1425–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a system of weights used for precious metals and gemstones, based on the grain, which is identical to the avoirdupois grain. 24 grains = 1 pennyweight; 20 pennyweights = 1 (troy) ounce; 12 ounces = 1 (troy) pound
Word Origin for troy weight
C14: named after the city of Troyes, France, where it was first used
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A system of weights and measures in which the grain is the same as in the avoirdupois system, and a pound contains 12 ounces, or 5,760 grains. Troy weight is used primarily by miners and gold dealers. Compare avoirdupois weight.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.