arm

1 of 5

noun (1)

ˈärm

plural arms

Synonyms of arm next

: a human upper limb

especially : the part between the shoulder and the wrist

: something like or corresponding to an arm: such as

: the forelimb of a vertebrate

: a limb of an invertebrate animal

: a branch or lateral shoot of a plant

: a slender part of a structure, machine, or an instrument projecting from a main part, axis, or fulcrum

: the end of a ship's yard

also : the part of an anchor from the crown to the fluke see anchor illustration

: any of the usually two parts of a chromosome lateral to the centromere

: an inlet of water (as from the sea)

: a narrow extension of a larger area, mass, or group

: power, might

the long arm of the law

: a support (as on a chair) for the elbow and forearm

: sleeve

: the ability to throw or pitch a ball well

also : a player having such ability

: a functional division of a group, organization, institution, or activity

the logistical arm of the air force

medical : a group of subjects provided a particular treatment in a clinical trial

Since this trial did not include a radiation-only treatment arm, it has been questioned whether radiation therapy alone might be as effective as sequential chemotherapy and radiation therapy in preserving the larynx.—

Everett E. Vokes et al.

armless

ˈärm-ləs

adjective

armlike

ˈärm-ˌlīk

adjective

arm

2 of 5

verb

armed; arming; arms

transitive verb

: to furnish or equip with weapons

: to furnish with something that strengthens or protects

arming citizens with the right to vote

: to equip or ready for action or operation

arm a bomb

intransitive verb

: to prepare oneself for struggle or resistance

arm for combat

arm

3 of 5

noun (2)

often attributive

: a means (such as a weapon) of offense or defense

especially : firearm

: a combat branch (as of an army)

: an organized branch of national defense (such as the navy)

arms plural

: the hereditary heraldic devices of a family

: heraldic devices adopted by a government

arms plural

: active hostilities : warfare

a call to arms

: military service

Arm

4 of 5

abbreviation (1)

Armenian

ARM

5 of 5

abbreviation (2)

adjustable rate mortgage

Phrases

arm in arm

: with arms linked together

up in arms

: aroused and ready to undertake a fight or conflict

Examples of arm in a Sentence

Verb They armed the men for battle. The group of fighters was armed by a foreign government. The two countries have been arming themselves for years, but now they have agreed to disarm. We armed ourselves with the tools we would need to survive in the forest. They arm people with accurate information. arming women with the right to vote Once the bomb has been armed, we have five minutes to escape.

Recent Examples on the Web

Noun

United States Air Force Cosme, who was struck in the head and the left arm, was unresponsive when team members arrived. —

Stephen Smith, CBS News, 8 Apr. 2024 He’s eventually cornered on a rooftop, raises his arms in surrender, then leaps to his death. —

Madeleine Marr, Miami Herald, 8 Apr. 2024 But Harry barely knew a word of English when his immigrant parents, Holocaust survivors with concentration-camp numbers tattooed on their arms, enrolled him at Rosemont Junior High in 1954. —

Hollace Ava Weiner, Fort Worth Star-Telegram, 8 Apr. 2024 After activating, slip the band on your arm and go to sleep. —

Latifah Miles, Parents, 8 Apr. 2024 Goodyear is developing special tires for the project (it’s been working with NASA since the Apollo missions), while MDA Space will be responsible for the vehicle’s robotic arm and interface. —

Bryan Hood, Robb Report, 8 Apr. 2024 So make sure your glasses are approved, undamaged and within arm's reach today. —

Jason Rossi, The Enquirer, 8 Apr. 2024 Commonly associated in the United States with on-campus hubs where students access dining halls, club offices, and social events, in the United Kingdom the union also takes on the form of a university-independent advocacy arm, lobbying at the institutional and national level. —

Leah Willingham, The Christian Science Monitor, 8 Apr. 2024 Tristen Newton fed him the ball at the top of the key, and Hawkins launched an off-balance jumper just as Butler caught him and extended an arm. —

Mark Zeigler, San Diego Union-Tribune, 28 Mar. 2024

Verb

Instead of his gear and gadgets, he is armed with only a diaper bag. —

Brent Lang, Variety, 10 Apr. 2024 Burrell was armed with a BB gun, according to a bond reduction motion his attorney filed. —

Emerson Clarridge, Fort Worth Star-Telegram, 9 Apr. 2024 Inside Randall Emmett’s crumbling empire June 30, 2022 In 1990, Cohen arrived in New York armed with a degree in broadcast journalism from Boston University and eclectic taste. —

Stacy Perman, Los Angeles Times, 3 Apr. 2024 Employers should be on the frontlines educating plan participants and arming them with the tools needed to utilize these accounts confidently. —

Brian Menickella, Forbes, 29 Mar. 2024 The Covid pandemic marked the first time people armed with powerful scientific tools could study how the immune system awakens to and develops defenses against a new threat, in real time, in the global population. —

Helen Branswell, STAT, 28 Mar. 2024 As tension bubbled, Zelaya armed himself with Corona beer bottles, the reports state. —

Grethel Aguila, Miami Herald, 29 Mar. 2024 Steps are being taken to better understand the decline and, once armed with that knowledge, slow or even stop it. —

M.d. Johnson, Field & Stream, 27 Mar. 2024 That would arm Hortiz with Harbaugh’s de facto top selection. —

Jeff Miller, Los Angeles Times, 25 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'arm.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun (1)

Middle English, going back to Old English earm, arm, going back to Germanic *arma-, masculine, (whence also Old Frisian erm "arm," Old Saxon arm, Old High German aram, arm, Old Norse armr, Gothic arms), going back to Indo-European *h₂orH-mo-, whence also Old Church Slavic ramo "shoulder," Bosnian-Croatian-Serbian rȁme, stem rȁmen-, Czech ráměk; a parallel zero-grade *h₂r̥H-mó- gives Old Prussian irmo "arm," Lithuanian (eastern dialects) ìrmėdė "pain from gout, chill, fever" (irm- "arm" + -ėdė "eating"), Sanskrit īrmá- "arm," Avestan arəma-; Latin armus "forequarter (of an animal), shoulder" probably goes back to *h₂erH-mo-

Note: Usually claimed to be a derivative of the verb *h₂er- "fit, join" (see arm entry 3)—very plausible semantically—though the Sanskrit and Baltic forms require a second laryngeal (*h₂erH-) in the base (cf. Rix et al., Lexikon der indogermanischen Verben, 2. Auflage, Wiesbaden, 2001, where the verbal base is posited without a second laryngeal). Could the suffix be *-H-mo-? The Slavic noun fluctuates in inflection between -mo- and -men- (see André Vaillant, Grammaire comparée des langues slaves, II:1 [Lyon, 1958], pp. 214-15). According to P. Schrijver, The Reflexes of the Proto-Indo-European Laryngeals in Latin (Amsterdam, 1991), p. 194, Latin armus cannot be traced to *h₂r̥H-mo-, which would have yielded *ramus. Regarding Armenian armukn "elbow," see H. K. Martirosyan, Etymological Dictionary of the Armenian Inherited Lexicon, Leiden, 2010, s.v.

Verb

Middle English armen, borrowed from Anglo-French armer, going back to Latin armāre, derivative of arma "implements of war, weapons, equipment" — more at arm entry 3

Noun (2)

Middle English armes (plural), "weapons, the military profession, heraldic devices," borrowed from Anglo-French, plural of arme "weapon," going back to Latin arma (neuter plural) "implements of war, weapons, equipment," derivative, with a suffix *-mo-, from a presumed verbal base *ar-, going back to Indo-European *h₂er- "fit, join," whence Greek reduplicated aorist ḗraron "(I) fit together, equipped, fit closely" (from which present tense ararískō, ararískein), ármenos (middle participle) "fitting, suited to," and (with suffixed *-smo- giving initial aspiration?) harmós "joint," hárma, harmat- "chariot, team of horses"; Armenian arari "(I) made," aṙnem "I make"

Note: See also art entry 1, arthro-, article entry 1, artiodactyl.

First Known Use

Noun (1)

before the 12th century, in the meaning defined at sense 1

Verb

13th century, in the meaning defined at transitive sense 2

Noun (2)

13th century, in the meaning defined at sense 1a

Time Traveler

The first known use of arm was before the 12th century

See more words from the same century

Cite this Entry

Style

“Arm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/arm. Accessed 16 Apr. 2024.

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Kids Definition

arm

1 of 3 noun

ˈärm

: a human upper limb

especially : the part between the shoulder and wrist

: a corresponding limb of a lower vertebrate animal

: something resembling an arm in shape or position

an arm of the sea

the arm of a chair

: power entry 1 sense 1a

the long arm of the law

: sleeve sense 1

armed

ˈärmd

adjective

armless

ˈärm-ləs

adjective

armlike

-ˌlīk

adjective

arm

2 of 3 verb

: to provide with weapons

arm a regiment

: to provide with a way of fighting, competing, or succeeding

armed herself with facts

: to make ready for action or use

arm a bomb

arm

3 of 3 noun

: weapon

especially : firearm

: a branch of an army

: a branch of the military forces

plural : the designs on a shield or flag of a family or a government

plural

: actual fighting : warfare

a call to arms

: military service

Etymology

Noun

Old English earm "arm"

Noun

Middle English armes "weapons," from early French armes (same meaning), from Latin arma "weapons" — related to alarm see Word History at alarm

Medical Definition

arm

noun

ˈärm

: a human upper limb

: the part of the human upper limb between the shoulder and the wrist

also : brachium

: the forelimb of a vertebrate other than a human being

: a limb of an invertebrate animal

: any of the usually two parts of a chromosome lateral to the centromere

: a group of subjects provided a particular treatment in a clinical trial

Since this trial did not include a radiation-only treatment arm, it has been questioned whether radiation therapy alone might be as effective as sequential chemotherapy and radiation therapy in preserving the larynx.—

Everett E. Vokes et al., The New England Journal of Medicine

Legal Definition

ARM

abbreviation

adjustable rate mortgage

Last Updated: 12 Apr 2024 - Updated example sentences

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arm

noun (1)

verb

noun (2)

abbreviation (1)

abbreviation (2)

Synonyms

Examples of arm in a Sentence

Word History

Dictionary Entries Near arm

Cite this Entry

Kids Definition

Medical Definition

Legal Definition