Noun
troy pound (plural troy pounds)
A unit of weight, rarely used except in the trade of precious metals, equal to 5760 troy grains, 12 troy ounces, or 373.2417 grams.
Apothecaries also used the troy pound and ounce, but added the drachms and scruples unit in the Apothecaries' system of weights. Source: Internet
Even though the troy pound was outlawed in the UK in the Weights and Measures Act of 1878, the troy ounce still may be used for the weight of precious stones and metals. Source: Internet
Later the avoirdupois ounce was standardised as 1 16 of a pound, but the troy ounce, which is 1 12 of a troy pound (a troy pound is lighter than an avoirdupois pound ), is still used for measuring precious metals. Source: Internet
Thus, 240 pennyweights made one troy pound of silver in weight, and the monetary value of 240 pennies also became known as a "pound". Source: Internet