What is the X in X-mas?
apothecaries' weight n.
A system of weights used in compounding prescriptions and in which an ounce equals 480 grains and a pound equals 12 ounces.
traditional system of weight in the British Isles used for the measuring and dispensing of pharmaceutical items and based on the grain, scruple (20 grains), dram (3 scruples), ounce (8 drams), and pound (12 ounces). The apothecaries' grain is equal to the troy and avoirdupois grains and represents 15,760 part of the troy and apothecaries' pound and 17,000 part of the avoirdupois pound. One apothecaries' pound equals approximately 0.82 avoirdupois pound, 373.24 grams, and 0.37 kilogram.