Source : Webster's Revised Unabridged Dictionary (1913)

Arm \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.

Arm \Arm\, n. [See {Arms}.] (Mil.)
      (a) A branch of the military service; as, the cavalry arm
          was made efficient.
      (b) A weapon of offense or defense; an instrument of
          warfare; -- commonly in the pl.

Arm \Arm\, v. t. [imp. & p. p. {Armed}; p. pr. & vb. n.
   {Arming}.] [OE. armen, F. armer, fr. L. armare, fr. arma,
   pl., arms. See {arms}.]
   1. To take by the arm; to take up in one's arms. [Obs.]

            And make him with our pikes and partisans A grave:
            come, arm him.                        --Shak.

            Arm your prize; I know you will not lose him. --Two
                                                  N. Kins.

   2. To furnish with arms or limbs. [R.]

            His shoulders broad and strong, Armed long and
            round.                                --Beau. & Fl.

   3. To furnish or equip with weapons of offense or defense;
      as, to arm soldiers; to arm the country.

            Abram . . . armed his trained servants. --Gen. xiv.
                                                  14.

   4. To cover or furnish with a plate, or with whatever will
      add strength, force, security, or efficiency; as, to arm
      the hit of a sword; to arm a hook in angling.

   5. Fig.: To furnish with means of defense; to prepare for
      resistance; to fortify, in a moral sense.

            Arm yourselves . . . with the same mind. --1 Pet.
                                                  iv. 1.

   {To arm a magnet}, to fit it with an armature.

Arm \Arm\, v. i.
   To provide one's self with arms, weapons, or means of attack
   or resistance; to take arms. `` 'Tis time to arm.'' --Shak.

Source : WordNet®

arm
     n 1: a human limb; technically the part of the superior limb
          between the shoulder and the elbow but commonly used to
          refer to the whole superior limb
     2: any instrument or instrumentality used in fighting or
        hunting; "he was licensed to carry a weapon" [syn: {weapon},
         {weapon system}]
     3: an administrative division of some larger or more complex
        organization; "a branch of Congress" [syn: {branch}, {subdivision}]
     4: any projection that is thought to resemble an arm; "the arm
        of the record player"; "an arm of the sea"; "a branch of
        the sewer" [syn: {branch}, {limb}]
     5: the part of an armchair or sofa that supports the elbow and
        forearm of a seated person
     6: the part of a garment that is attached at armhole and
        provides a cloth covering for the arm [syn: {sleeve}]

arm
     v 1: prepare oneself for a military confrontation; "The U.S. is
          girding for a conflict in the Middle East"; "troops are
          building up on the Iraqui border" [syn: {build up}, {fortify},
           {gird}] [ant: {disarm}]
     2: supply with arms; "The U.S. armed the freedom fighters in
        Afghanistan"

Source : Free On-Line Dictionary of Computing

ARM
     
        1.  {Advanced RISC Machine}.
     
        Originally {Acorn} RISC Machine.
     
        2.  {Advanced RISC Machines} Ltd.
     
        3.  ["The Annotated C++ Reference Manual",
        Margaret A. Ellis and Bjarne Stroustrup, Addison-Wesley,
        1990].
     
        4.  {Active Reconfiguring Message}.
     
        (1997-10-03)