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Related to Troy Weight: avoirdupois ounce, OZT
A system to measure mass. It originated in the Middle Ages in France and is arranged into (from lightest to heaviest) grains, pennyweights, ounces and pounds. Of these, only troy ounces are still used, and only to weigh precious metals. A troy ounce is heavier than an imperial ounce but lighter than an imperial pound.