COG. (1) (From an older cogge, a word which appears in various forms in Teutonic languages, as in O. Ger. kogge or kocke, and also in Romanic, as in O. Fr. cogue, or coque, from which the Eng. "cock-boat" is derived; the connexion between the Teutonic and the Romanic forms is obscure), a broadly built, round-shaped ship, used as a trader and also as a ship of war till the 15th century. (2) (A word of obscure origin, possibly connected with Fr. coche, and Ital. cocca, a notch; the Celtic forms cog and cocas come from the English), a tooth in a series of teeth, morticed on to, or cut out of the circumference of a wheel, which works with the tooth in a corresponding series on another wheel (see Mechanics). (3) (Also of quite obscure origin), a slang term for a form of cheating at dice. The early uses of the word show that this was done not by "loading" the dice, as the modern use of the expression of "cogged dice" seems to imply, but by sleight of hand in directing the fall or in changing the dice.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)