GRAIN, the seed, or "fruit," cereals, and hence cereal plants generally (from Lat. granum, seed). (See GRAIN PRODUC TION.) The word is also used of the malt refuse of brewing and distilling, and of many hard rounded small particles, such as "grains" of sand, salt, gold, gunpowder, etc. A "grain" is also the smallest unit of weight, both in Great Britain and the United States of America. Its origin is supposed to be the weight of a grain of wheat. The troy grain ;so of a lb., the avoirdupois grain = - oo of a lb. In diamond weighing the grain = a of the carat = • 79 2 5 of the troy grain. The word "grains" was early used of the small seed-like insects supposed formerly to be the berries of trees, from which a scarlet dye was extracted (see COCHINEAL and KERMES). The imitating in paint of the grain of wood is called "graining" (see PAINTER-WORK IN THE BUILDING TRADE).