GRAIN (derived through the French from Lat. granum, seed, from an Aryan root meaning " to wear down," which also appears in the common Teutonic word " corn "), a word particularly applied to the seed, in botanical language the " fruit," of cereals, and hence applied, as a collective term to cereal plants generally, to which, in English, the term " corn " is also applied (see GRAIN TRADE). Apart from this, the chief meaning, the word is used of the malt refuse of brewing and distilling, and of many hard rounded small particles, resembling the seeds of plants, such as " grains " of sand, salt, gold, gunpowder, etc. " Grain " is also the name of the smallest unit of weight, both in the .United Kingdom and the United States of America. Its origin is supposed to be the weight of a grain of wheat, dried and gathered from the middle of the ear. The troy grain= 1/5760 of a ft, the avoirdupois grain =1/7000 of a ft. In diamond weighing the grain = j of the carat, = -7925 of the troy grain. The word " grains " was early used, as also in French, 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). From the Fr. en graine, literally in dye, comes the French verb engrainer, Eng. " engrain " or " ingrain," meaning to dye in any fast colour. From the further use of " grain " for the texture of substances, such as wood, meat, etc., " engrained " or " ingrained " means ineradicable, impregnated, dyed through and through. The " grain " of leather is the side of a skin showing the fibre after the hair has been removed. The imitating in paint of the grain of different kinds of woods is known as " graining " (see PAINTER- WORK). " Grain," or more commonly in the plural " grains," construed as a singular, is the name of an instrument with two or more barbed prongs, used for spearing fish. This word is Scandinavian in origin, and is connected with Dan. green, Swed. gren, branch, and means the fork of a tree, of the body, or the prongs of a fork, etc. It is not connected with " groin," the inguinal parts of the body, which in its earliest forms appears as grynde.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)