Āv'oir-du-pois', a.

(ăv'er-du-poiz', 38), a. [Fr. avoir du poids, to have [a fixed or standard] weight, from Fr. avoir, to have, from Lat. habere, and Fr. poids, O. Fr. poix, pois, from Lat. pensum, a portion weighed, from pensus, p. p. of pendere, to weigh. The d in the modern form of the French word has been erroneously added, because the word was thought to be derived from Lat. pondus, weight.] A system of weights by which coarser commodities are weighed, such as hay, grain, &c. The standard avoirdupois pound of the United States is equivalent to the weight of 27.7015 cubic inches of distilled water at 62° Fahrenheit, the barometer being at 30 inches, and the water weighed with brass weights in the air. In this system of weights 16 drams make 1 ounce, 16 ounces 1 pound, 25 pounds 1 quarter, 4 quarters 1 hundred weight, and 20 hundred weight 1 ton. The pound contains 7000 grains, so that 1 pound avoirdupois is equivalent to 1 31-144 pounds troy. Formerly, a hundred weight was reckoned at 112 pounds, but now at 100. Math. Dict.