1. The limb of the human body which extends from the shoulder to the hand; also, the corresponding limb of a monkey. 2. Anything resembling an arm; as, (a) The fore limb of an animal, as of a bear. (b) A limb, or locomotive or prehensile organ, of an invertebrate animal. (c) A branch of a tree. (d) A slender part of an instrument or machine, projecting fr...