WordReference Random House Learner's Dictionary of American English © 2020
arm1 /ɑrm/USA pronunciation   n. [countable]
  1. Anatomy
    • the upper limb of the human body.
    • the upper limb from shoulder to elbow:The doctor gave me an injection in the arm.
  2. Sound Reproductionany part or attachment that resembles an arm, as a projecting support on a chair.
  3. a branch, section, or part of an organization: an arm of the government.
  1. Idiomsan arm and a leg, a great deal of money: That will cost an arm and a leg.
  2. Idiomsarm in arm, with arms linked together or intertwined: walking along arm in arm.
  3. Idiomsat arm's length, at a distance that discourages intimacy:kept her associates at arm's length.
  4. (long) arm of the law, the power or authority of the law or law enforcement.
  5. Idiomstwist someone's arm, to bring strong pressure to bear on someone.
  6. Idiomswith open arms, cordially;
    hospitably:welcomed her with open arms.

arm2 /ɑrm/USA pronunciation   n. 
  1. MilitaryUsually, arms. [plural] weapons, esp. guns, rifles, or firearms.
  2. Heraldry arms, [plural] the heraldic designs or symbols on a shield.

  1. to (cause to) be equipped with weapons: [no object]The country is arming for war.[~ + oneself]The rebels armed themselves.[~ + object]They armed their troops.
  2. to activate, equip, or prepare (something) for specific purpose or effective use:[~ + object]to arm the security system.
  1. Idioms, Militarybear arms: 
    • to carry weapons:claimed the right to bear arms.
    • to serve as a member of the armed forces:He had to bear arms as a youth of only sixteen.
  2. Idioms, Militarytake up arms, to prepare for or go to war.
  3. Idioms, Militaryunder arms, (of troops) trained and equipped for battle.
  4. Idiomsup in arms, indignant:is up in arms about the effort to discredit him.

-arm-, root. 
  1. -arm- comes from Latin, where it has the meaning "weapon.'' This meaning is found in such words as: armada, armament, arms, disarmament.

WordReference Random House Unabridged Dictionary of American English © 2020
arm1  (ärm),USA pronunciation n. 
  1. Anatomythe upper limb of the human body, esp. the part extending from the shoulder to the wrist.
  2. Anatomythe upper limb from the shoulder to the elbow.
  3. Biologythe forelimb of any vertebrate.
  4. Zoologysome part of an organism like or likened to an arm.
  5. Sound Reproductionany armlike part or attachment, as the tone arm of a phonograph.
  6. a covering for the arm, esp. a sleeve of a garment:the arm of a coat.
  7. an administrative or operational branch of an organization:A special arm of the government will investigate.
  8. Nautical, Naval Termsany of the curved or bent pieces of an anchor, terminating in the flukes. See diag. under  anchor. 
  9. Furniturean armrest.
  10. an inlet or cove:an arm of the sea.
  11. Militarya combat branch of the military service, as the infantry, cavalry, or field artillery.
  12. power;
    authority:the long arm of the law.
  13. Printing[Typography.]either of the extensions to the right of the vertical line of a K or upward from the vertical stem of a Y.
  14. an arm and a leg, a great deal of money:Our night on the town cost us an arm and a leg.
  15. arm in arm, with arms linked together or intertwined:They walked along arm in arm.
  16. at arm's length, not on familiar or friendly terms;
    at a distance:He's the kind of person you pity but want to keep at arm's length.
  17. in the arms of Morpheus, asleep:After a strenuous day, he was soon in the arms of Morpheus.
  18. on the arm, [Slang.]free of charge;
    gratis:an investigation of policemen who ate lunch on the arm.
  19. put the arm on, [Slang.]
    • to solicit or borrow money from:She put the arm on me for a generous contribution.
    • to use force or violence on;
      use strong-arm tactics on:If they don't cooperate, put the arm on them.
  20. twist someone's arm, to use force or coercion on someone.
  21. with open arms, cordially;
    with warm hospitality:a country that receives immigrants with open arms.
armed, adj. 
armlike′, adj. 
  • bef. 900; Middle English; Old English earm; cognate with Gothic arms, Old Norse armr, Old Frisian erm, Dutch, Old Saxon, Old High German arm (German Arm) arm; Latin armus, Serbo-Croatian rȁme, rȁmo shoulder; akin to Sanskrit īrmá, Avestan arəma-, Old Prussian irmo arm; not akin to Latin arma arm2

arm2  (ärm),USA pronunciation n. 
  1. MilitaryUsually,  arms. weapons, esp. firearms.
  2. Heraldryarms, the escutcheon, with its divisions, charges, and tinctures, and the other components forming an achievement that symbolizes and is reserved for a person, family, or corporate body;
    armorial bearings;
    coat of arms.
  3. Militarybear arms: 
    • to carry weapons.
    • to serve as a member of the military or of contending forces:His religious convictions kept him from bearing arms, but he served as an ambulance driver with the Red Cross.
  4. Militarytake up arms, to prepare for war;
    go to war:to take up arms against the enemy.
  5. Militaryunder arms, ready for battle;
    trained and equipped:The number of men under arms is no longer the decisive factor in warfare.
  6. up in arms, ready to take action;
    outraged:There is no need to get up in arms over such a trifle.

  1. to enter into a state of hostility or of readiness for war.

  1. to equip with weapons:to arm the troops.
  2. to activate (a fuze) so that it will explode the charge at the time desired.
  3. to cover protectively.
  4. to provide with whatever will add strength, force, or security;
    fortify:He was armed with statistics and facts.
  5. to equip or prepare for any specific purpose or effective use:to arm a security system; to arm oneself with persuasive arguments.
  6. to prepare for action;
    make fit;
armless, adj. 
  • Latin armāre to arm, verb, verbal derivative of arma (plural) tools, weapons (not akin to arm1); (noun, nominal) Middle English armes (plural) Latin arma, as above
  • Anglo-French, Old French armer
  • 1200–50 for verb, verbal; 1300–50 for noun, nominal; (verb, verbal) Middle English armen
    • 12.See corresponding entry in Unabridged outfit.
    • 9.See corresponding entry in Unabridged deactivate, disarm.

  • Businessadjustable-rate mortgage.

  • Arm, 
  • Language VarietiesArmenian.

  • Arm., 
    1. Language VarietiesArmenian.
    2. Armorican.

  • Master of Architecture.
    • Neo-Latin Architecturae Magister

    Collins Concise English Dictionary © HarperCollins Publishers::
    arm /ɑːm/ n
    1. (in man) either of the upper limbs from the shoulder to the wrist
      Related adjective(s): brachial
    2. the part of either of the upper limbs from the elbow to the wrist; forearm
    3. the corresponding limb of any other vertebrate
    4. an armlike appendage of some invertebrates
    5. an object that covers or supports the human arm, esp the sleeve of a garment or the side of a chair, sofa, etc
    6. anything considered to resemble an arm in appearance, position, or function, esp something that branches out from a central support or larger mass: an arm of the sea, the arm of a record player
    7. an administrative subdivision of an organization: an arm of the government
    8. power; authority: the arm of the law
    9. arm in armwith arms linked
    10. at arm's lengthat a distance; away from familiarity with or subjection to another
    11. in the arms of Morpheussleeping
    12. with open armswith great warmth and hospitality: to welcome someone with open arms
    Etymology: Old English; related to German Arm, Old Norse armr arm, Latin armus shoulder, Greek harmos joint
    arm /ɑːm/ vb (transitive)
    1. to equip with weapons as a preparation for war
    2. to provide (a person or thing) with something that strengthens, protects, or increases efficiency
    3. to activate (a fuse) so that it will explode at the required time
    4. to prepare (an explosive device) for use by introducing a fuse or detonator
    1. (usually plural) a weapon, esp a firearm

    See also armsEtymology: 14th Century: (n) back formation from arms, from Old French armes, from Latin arma; (vb) from Old French armer to equip with arms, from Latin armāre, from arma arms, equipment
    'with open arms' also found in these entries:
    arm - open

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