1 [ahrm]
the upper limb of the human body, especially the part extending from the shoulder to the wrist.
the upper limb from the shoulder to the elbow.
the forelimb of any vertebrate.
some part of an organism like or likened to an arm.
any armlike part or attachment, as the tone arm of a phonograph.
a covering for the arm, especially a sleeve of a garment: the arm of a coat.
an administrative or operational branch of an organization: A special arm of the government will investigate.
Nautical. any of the curved or bent pieces of an anchor, terminating in the flukes.
an armrest.
an inlet or cove: an arm of the sea.
a combat branch of the military service, as the infantry, cavalry, or field artillery.
power; might; strength; authority: the long arm of the law.
Typography. either of the extensions to the right of the vertical line of a K or upward from the vertical stem of a Y.
an arm and a leg, a great deal of money: Our night on the town cost us an arm and a leg.
arm in arm, with arms linked together or intertwined: They walked along arm in arm.
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.
in the arms of Morpheus, asleep: After a strenuous day, he was soon in the arms of Morpheus.
on the arm, Slang. free of charge; gratis: an investigation of policemen who ate lunch on the arm.
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.
twist someone's arm, to use force or coercion on someone.
with open arms, cordially; with warm hospitality: a country that receives immigrants with open arms.

before 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-, OPruss irmo arm; not akin to Latin arma arm2

armed, adjective
armlike, adjective

alms, arms. Unabridged


2 [ahrm]
Usually, arms. weapons, especially firearms.
arms, Heraldry. 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.
verb (used without object)
to enter into a state of hostility or of readiness for war.
verb (used with object)
to equip with weapons: to arm the troops.
to activate (a fuze) so that it will explode the charge at the time desired.
to cover protectively.
to provide with whatever will add strength, force, or security; support; fortify: He was armed with statistics and facts.
to equip or prepare for any specific purpose or effective use: to arm a security system; to arm oneself with persuasive arguments.
to prepare for action; make fit; ready.
bear 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.
take up arms, to prepare for war; go to war: to take up arms against the enemy.
under arms, ready for battle; trained and equipped: The number of men under arms is no longer the decisive factor in warfare.
up in arms, ready to take action; indignant; outraged: There is no need to get up in arms over such a trifle.

1200–50 for v.; 1300–50 for noun; (v.) Middle English armen < Anglo-French, Old French armer < Latin armāre to arm, verbal derivative of arma (plural) tools, weapons (not akin to arm1); (noun) Middle English armes (plural) ≪ Latin arma, as above

armless, adjective

8. outfit.

5. deactivate, disarm.


adjustable-rate mortgage.




Master of Architecture.

< New Latin Architecturae Magister Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source Link To arm
World English Dictionary
arm1 (ɑːm)
1.  (in man) either of the upper limbs from the shoulder to the wristRelated: brachial
2.  the part of either of the upper limbs from the elbow to the wrist; forearm
3.  a.  the corresponding limb of any other vertebrate
 b.  an armlike appendage of some invertebrates
4.  an object that covers or supports the human arm, esp the sleeve of a garment or the side of a chair, sofa, etc
5.  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
6.  an administrative subdivision of an organization: an arm of the government
7.  power; authority: the arm of the law
8.  any of the specialist combatant sections of a military force, such as cavalry, infantry, etc
9.  nautical See yardarm
10.  esp sport, ball games ability to throw or pitch: he has a good arm
11.  informal an arm and a leg a large amount of money
12.  arm in arm with arms linked
13.  at arm's length at a distance; away from familiarity with or subjection to another
14.  informal give one's right arm to be prepared to make any sacrifice
15.  in the arms of Morpheus sleeping
16.  with open arms with great warmth and hospitality: to welcome someone with open arms
17.  archaic (tr) to walk arm in arm with
Related: brachial
[Old English; related to German Arm, Old Norse armr arm, Latin armus shoulder, Greek harmos joint]

arm2 (ɑːm)
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: he armed himself against the cold
3.  a.  to activate (a fuse) so that it will explode at the required time
 b.  to prepare (an explosive device) for use by introducing a fuse or detonator
4.  nautical to pack arming into (a sounding lead)
5.  (usually plural) a weapon, esp a firearm
[C14: (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]

abbreviation for
adjustable rate mortgage

abbreviation for

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

"body part," O.E. earm "arm," from P.Gmc. *armaz (cf. O.S., M.Du., Ger. arm, O.N. armr, O.Fris. erm), from PIE base *ar- "fit, join" (cf. Skt. irmah "arm," Armenian armukn "elbow," O.Prus. irmo "arm," Gk. arthron "a joint," L. armus "shoulder"). Arm of the sea was in O.E. Arm-twister "powerful persuader"
is from 1938. Arm-wrestling is from 1971.
"They wenten arme in arme yfere Into the gardyn" [Chaucer]

"weapon," c.1300, from O.Fr. armes (pl.), 11c., from L. arma "weapons," lit. "tools, implements (of war)," from PIE base *ar- "fit, join." The notion seems to be "that which is fitted together." Meaning "heraldic insignia" (in coat of arms, etc.) is early 14c.; originally they were borne on shields of
fully armed knights or barons. The verb meaning "to furnish with weapons" is from c.1200.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

arm 1 (ärm)
An upper limb of the human body, connecting the hand and wrist to the shoulder.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Computing Dictionary

ARM definition

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.
The Free On-line Dictionary of Computing, © Denis Howe 2010
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American Heritage
Abbreviations & Acronyms
  1. adjustable rate mortgage

  2. Alien Resistance Movement

  3. antiradiation missile

  4. Armenia (international vehicle ID)

  1. Armenia

  2. Armenian

The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Bible Dictionary

Arm definition

used to denote power (Ps. 10:15; Ezek. 30:21; Jer. 48:25). It is also used of the omnipotence of God (Ex. 15:16; Ps. 89:13; 98:1; 77:15; Isa. 53:1; John 12:38; Acts 13:17)

Easton's 1897 Bible Dictionary
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American Heritage
Idioms & Phrases


In addition to the idioms beginning with arm, also see at arm's length; babe in arms; forewarned is forearmed; give one's eyeteeth (right arm); long arm of the law; one-armed bandit; put the arm on; shot in the arm; take up arms; talk someone's arm off; twist someone's arm; up in arms; with one arm tied behind; with open arms.

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Example sentences for arm
This increases the energy output, even with an arm with less mechanical
The army does not currently have plans to arm the shadow with light munitions.
A pronating wristlock that torques the arm and applies painful nerve pressure.
Monkey controls robotic arm using brain signals sent over internet.
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