GALL, the secretion of the liver known as "bile," the term being also used of the pear-shaped diverticulum of the bile-duct, which forms a reservoir for the bile, more generally known as the "gall-bladder" (see LIVER). From the extreme bitterness of the secretion, "gall," like the Lat. fel, is used for anything ex tremely bitter, whether actually or metaphorically.
"Gall," meaning a sore or painful swelling, especially on a horse, may be derived from an early use of the word as mean ing "poison." But in Romanic languages, the Fr. galle, Sp. agalla, a wind-gall or puffy distension of the synovial bursa on the fetlock joint of a horse, is derived from the Lat. galls, oak apple, from which comes the English "gall," meaning an ex crescence on trees caused by certain insects. (See GALLS.)