Dictionary.com
definitions

arm

2
[ahrm]
||
SEE MORE SYNONYMS FOR arm ON THESAURUS.COM

noun

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)

Idioms

    bear arms,
    1. to carry weapons.
    2. 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.

Origin of arm

2
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
Related formsarm·less, adjective

Synonyms for arm

SEE MORE SYNONYMS FOR arm ON THESAURUS.COM
8. outfit.

Antonyms for arm

5. deactivate, disarm.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for up in arms

hostile, provoked
British Dictionary definitions for up in arms

arm

1

noun

(in man) either of the upper limbs from the shoulder to the wristRelated adjective: brachial
the part of either of the upper limbs from the elbow to the wrist; forearm
  1. the corresponding limb of any other vertebrate
  2. an armlike appendage of some invertebrates
an object that covers or supports the human arm, esp the sleeve of a garment or the side of a chair, sofa, etc
anything considered to resemble an arm in appearance, position, or function, esp something that branches out from a central support or larger massan arm of the sea; the arm of a record player
an administrative subdivision of an organizationan arm of the government
power; authoritythe arm of the law
any of the specialist combatant sections of a military force, such as cavalry, infantry, etc
nautical See yardarm
sport, esp ball games ability to throw or pitchhe has a good arm
an arm and a leg informal a large amount of money
arm in arm with arms linked
at arm's length at a distance; away from familiarity with or subjection to another
give one's right arm informal to be prepared to make any sacrifice
in the arms of Morpheus sleeping
with open arms with great warmth and hospitalityto welcome someone with open arms

verb

(tr) archaic to walk arm in arm with
Derived Formsarmless, adjectivearmlike, adjective

Word Origin for arm

Old English; related to German Arm, Old Norse armr arm, Latin armus shoulder, Greek harmos joint

arm

2

verb (tr)

to equip with weapons as a preparation for war
to provide (a person or thing) with something that strengthens, protects, or increases efficiencyhe armed himself against the cold
  1. to activate (a fuse) so that it will explode at the required time
  2. to prepare (an explosive device) for use by introducing a fuse or detonator
nautical to pack arming into (a sounding lead)

noun

(usually plural) a weapon, esp a firearm
See also arms

Word Origin for arm

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

ARM

abbreviation for

adjustable rate mortgage
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for up in arms

arm

n.1

"upper limb," Old English earm "arm," from Proto-Germanic *armaz (cf. Old Saxon, Danish, Swedish, Middle Dutch, German arm, Old Norse armr, Old Frisian erm), from PIE root *ar- "fit, join" (cf. Sanskrit irmah "arm," Armenian armukn "elbow," Old Prussian irmo "arm," Greek arthron "a joint," Latin armus "shoulder"). Arm of the sea was in Old English. Arm-twister "powerful persuader" is from 1938. Arm-wrestling is from 1899.

They wenten arme in arme yfere Into the gardyn [Chaucer]

arm

n.2

"weapon," c.1300, armes (plural) "weapons of a warrior," from Old French armes (plural), "arms, war, warfare," mid-13c., from Latin arma "weapons" (including armor), literally "tools, implements (of war)," from PIE root *ar- "fit, join" (see arm (n.1)). 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.

arm

v.

"to furnish with weapons," c.1200, from Old French armer or directly from Latin armare, from arma (see arm (n.2)). Related: Armed; arming.

Online Etymology Dictionary, © 2010 Douglas Harper
up in arms in Medicine

arm

[ärm]

n.

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.
Idioms and Phrases with up in arms

up in arms

Angry, rebellious, as in The town was up in arms over the state's plan to allow commercial flights at the air base. This idiom originally referred to an armed rebellion and was so used from the late 1500s. Its figurative use dates from about 1700.

arm

In addition to the idioms beginning with arm

  • arm and a leg
  • armed to the teeth
  • arm in 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® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.