Arm (�), n. [AS. arm, earm; akin to OHG. aram, G., D., Dan., & Sw. arm, Icel. armr, Goth. arms, L. armus arm, shoulder, and prob. to Gr. � joining, joint, shoulder, fr. the root � to join, to fit together; cf. Slav. rame. �. See Art, Article.] 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 from a trunk, axis, or fulcrum; as, the arm of a steelyard. (e) (Naut) The end of a yard; also, the part of an anchor which ends in the fluke. (f) An inlet of water from the sea. (g) A support for the elbow, at the side of a chair, the end of a sofa, etc.
3. Fig.: Power; might; strength; support; as, the secular arm; the arm of the law.
To whom is the arm of the Lord revealed?
Isa. lii. 1.
Arm's end, the end of the arm; a good distance off. Dryden. — Arm's length, the length of the arm. — Arm's reach, reach of the arm; the distance the arm can reach. — To go (or walk) arm in arm, to go with the arm or hand of one linked in the arm of another. “When arm in armwe went along.” Tennyson. — To keep at arm's length, to keep at a distance (literally or figuratively); not to allow to come into close contact or familiar intercourse. — To work at arm's length, to work disadvantageously.