Arm and a leg

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 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 .
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.
noun
(in man) either of the upper limbs from the shoulder to the wrist related adjective brachial
the part of either of the upper limbs from the elbow to the wrist; forearm

the corresponding limb of any other vertebrate
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 m-ss: an arm of the sea, the arm of a record player
an administrative subdivision of an organization: an arm of the government
power; authority: the arm of the law
any of the specialist combatant sections of a military force, such as cavalry, infantry, etc
(nautical) see yardarm
(sport) especially (ball games) ability to throw or pitch: he has a good arm
(informal) an arm and a leg, 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
(informal) give one’s right arm, to be prepared to make any sacrifice
in the arms of morpheus, sleeping
with open arms, with great warmth and hospitality: to welcome someone with open arms
verb
(transitive) (archaic) to walk arm in arm with
verb (transitive)
to equip with weapons as a preparation for war
to provide (a person or thing) with something that strengthens, protects, or increases efficiency: he armed himself against the cold

to activate (a fuse) so that it will explode at the required time
to prepare (an explosive device) for use by introducing a fuse or detonator

(nautical) to pack arming into (a sounding lead)
noun
(usually pl) a weapon, esp a firearm
abbreviation
adjustable rate mortgage
n.

“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]

“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.
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.

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

noun

a police officer

verb

highflag (cabdrivers)

related terms

as long as your arm, crooked arm, one-arm bandit, ride the arm, stiff, twist someone’s arm

[police sense fr arm of the law]
adjustable rate mortgage
alien resistance movement
antiradiation missile
armenia (international vehicle id)

used to denote power (ps. 10:15; ezek. 30:21; jer. 48:25). it is also used of the omnipotence of g-d (ex. 15:16; ps. 89:13; 98:1; 77:15; isa. 53:1; john 12:38; acts 13:17)

an exorbitant amount of money, as in these resort hotels charge an arm and a leg for a decent meal, or fixing the car is going to cost an arm and a leg. according to eric partridge, this hyperbolic idiom, which is always used in conjunction with verbs such as “cost,” “charge,” or “pay,” and became widely known from the 1930s on, probably came from the 19th-century american criminal slang phrase, if it takes a leg (that is, even at the cost of a leg), to express desperate determination.

arm and a leg
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