An arm is a limb on the upper part of a person's body. You can call the front limb of any animal an arm, though they're more often called "legs."

Starfish have five arms, while humans have two. The sleeves of your shirt are arms too, and an excellent baseball pitcher is said to have "an arm," meaning a powerful throw. When arm is a verb, it means "supply with weapons." These meanings have two different roots: an arm with a hand on the end comes from the Old English earm, while the weapon arm is rooted in the Latin arma, or "weapons."

Primary Meanings of arm

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
any instrument or instrumentality used in fighting or hunting
prepare oneself for a military confrontation
Full Definitions of arm

n 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

Type of:
one of the jointed appendages of an animal used for locomotion or grasping: arm; leg; wing; flipper

n the part of a garment that is attached at the armhole and that provides a cloth covering for the arm

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dolman sleeve
a sleeve with a large armhole and tight cuff
long sleeve
a sleeve extending from shoulder to wrist
raglan sleeve
a sleeve that extends in one piece to the neckline of a coat or sweater with seams from the armhole to the neck
the sleeve of a shirt
short sleeve
a sleeve extending from the shoulder to the elbow
Type of:
cloth covering
a covering made of cloth

n the part of an armchair or sofa that supports the elbow and forearm of a seated person

writing arm
an arm of a tablet-armed chair; widened to provide a writing surface
Type of:
a support for the arm

n any projection that is thought to resemble a human arm

“the arm of the record player”
“an arm of the sea”
branch, limb
Type of:
any structure that branches out from a central support

n a division of some larger or more complex organization

branch, subdivision
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local post office, post office
a local branch where postal services are available"
Executive Office of the President, executive branch
the branch of the United States government that is responsible for carrying out the laws
legislative branch
the branch of the United States government that has the power of legislating
judicial branch
the branch of the United States government responsible for the administration of justice
Type of:
an administrative unit in government or business

n any instrument or instrumentality used in fighting or hunting

weapon, weapon system
the legendary sword of King Arthur
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a weapon for shooting arrows, composed of a curved piece of resilient wood with a taut cord to propel the arrow
bow and arrow
a weapon consisting of arrows and the bow to shoot them
brass knuckles, brass knucks, knuckle duster, knuckles, knucks
a small metal weapon; worn over the knuckles on the back of the hand
fire ship
a weapon consisting of a ship carrying explosives that is set adrift to destroy enemy ships
a weapon that squirts ignited fuel for several yards
a weapon that discharges a missile at high velocity (especially from a metal tube or barrel)
a weapon with a handle and blade with a sharp point
light arm
a rifle or pistol
a rocket carrying a warhead of conventional or nuclear explosives; may be ballistic or directed by remote control
medieval weapon consisting of a spearhead attached to a long pole or pikestaff; superseded by the bayonet
missile, projectile
a weapon that is forcibly thrown or projected at a targets but is not self-propelled
a weapon (a sword or dagger) used for slashing
a simple weapon consisting of a looped strap in which a projectile is whirled and then released
lance, shaft, spear
a long pointed rod used as a tool or weapon
stun baton, stun gun
a weapon designed to disable a victim temporarily by delivering a nonlethal high-voltage electric shock
blade, brand, steel, sword
a cutting or thrusting weapon that has a long metal blade and a hilt with a hand guard
hatchet, tomahawk
weapon consisting of a fighting ax; used by North American Indians
W.M.D., WMD, weapon of mass destruction
a weapon that kills or injures civilian as well as military personnel (nuclear and chemical and biological weapons)
Greek fire
a mixture used by Byzantine Greeks that was often shot at adversaries; catches fire when wetted
air gun, air rifle, airgun
a gun that propels a projectile by compressed air
air-to-air missile
a missile designed to be launched from one airplane at another
air-to-ground missile, air-to-surface missile
a missile designed to be launched from an airplane at a target on the ground
ack-ack, ack-ack gun, antiaircraft, antiaircraft gun, flack, flak, pom-pom
artillery designed to shoot upward at airplanes
a projectile with a straight thin shaft and an arrowhead on one end and stabilizing vanes on the other; intended to be shot from a bow
assagai, assegai
the slender spear of the Bantu-speaking people of Africa
a sword with only one cutting edge
ballistic missile
a missile that is guided in the first part of its flight but falls freely as it approaches target
a knife that can be fixed to the end of a rifle and used as a weapon
bioarm, biological weapon, bioweapon
any weapon usable in biological warfare
boomerang, throw stick, throwing stick
a curved piece of wood; when properly thrown will return to thrower
a gun that is loaded at the breech
a sword with a broad blade and (usually) two cutting edges; used to cut rather than stab
bullet, slug
a projectile that is fired from a gun
heavy automatic gun fired from an airplane
heavy gun fired from a tank
cannon ball, cannonball, round shot
a solid projectile that in former times was fired from a cannon
cavalry sword, saber, sabre
a stout sword with a curved blade and thick back
chemical weapon
chemical substances that can be delivered using munitions and dispersal devices to cause death or severe harm to people and animals and plants
a bow fixed transversely on a wooden stock grooved to direct the arrow (quarrel)
Cupid's bow
a curved bow with reversed curve ends
cutlas, cutlass
a short heavy curved sword with one edge; formerly used by sailors
dagger, sticker
a short knife with a pointed blade used for piercing or stabbing
a small narrow pointed missile that is thrown or shot
a short broad slightly convex medieval sword with a sharp point
fencing sword
a sword used in the sport of fencing
firearm, piece, small-arm
a portable gun
gas gun
a gun that fires gas shells
guided missile
a rocket-propelled missile whose path can be controlled during flight either by radio signals or by internal homing devices
a pike fitted with an ax head
a bow drawn by hand as distinguished from a crossbow
heat-seeking missile
a missile with a guidance system that directs it toward targets emitting infrared radiation (as the emissions of a jet engine)
a spear thrown as a weapon or in competitive field events
a curved steel knife with a razor-sharp edge used in combat by the Gurkhas; has cultural and religious significance in Nepal
a powerful wooden bow drawn by hand; usually 5-6 feet long; used in medieval England
machete, matchet, panga
a large heavy knife used in Central and South America as a weapon or for cutting vegetation
minute gun
(military) gun that is discharged once every minute (usually as part of a military funeral)
atomic weapon, nuclear weapon
a weapon of mass destruction whose explosive power derives from a nuclear reaction
partisan, partizan
a pike with a long tapering double-edged blade with lateral projections; 16th and 17th centuries
Quaker gun
a dummy gun or piece of artillery made usually of wood
rapier, tuck
a straight sword with a narrow blade and two edges
a missile equipped with a device that is attracted toward some kind of emission (heat or light or sound or radio waves)
set gun, spring gun
a gun that is set to fire on any intruder that comes in contact with the wire that sets it off
a knife used as a weapon
pellet, shot
a solid missile discharged from a firearm
air-to-air missile with infrared homing device
a projectile made by chewing a piece of paper and shaping it into a sphere
trench knife
a knife with a double-edged blade for hand-to-hand fighting
a spear with three prongs
a kind of pike used by foot soldiers in the 14th century
whaling gun
a gun (or device resembling a gun) for discharging a projectile (especially a harpoon) at a whale
a long Turkish knife with a curved blade having a single edge
high explosive
a powerful chemical explosive that produces gas at a very high rate
Type of:
a device that requires skill for proper use

v prepare oneself for a military confrontation

build up, fortify, gird
demilitarise, demilitarize, disarm
remove offensive capability from
re-arm, rearm
arm anew
arm in advance of a confrontation

v supply with arms

“The U.S. armed the freedom fighters in Afghanistan”
supply with weapons
arm again
Type of:
furnish, provide, render, supply
give something useful or necessary to

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