1arm 
/ˈɑɚm/ noun
plural arms /ˈɑɚm/ noun [count] 1 : either one of the two long body parts that join the top of your body at the shoulder and that end at the hand or wrist
▪ He has big, strong, muscular arms. ▪ She broke her left arm. = Her left arm was/got broken. ▪ He hurt his throwing/pitching arm [=the arm that he uses to throw/pitch a ball] in the last game. ▪ She put/threw her arms around him. [=she hugged him] ▪ She had a newspaper tucked under her arm. ▪ He was carrying a bag of groceries in each arm. ▪ He gave/offered his arm to her, and she took it. [=she held onto his arm] ▪ She grabbed my arm. = She grabbed me by the arm. ▪ He was standing there with his arms crossed/folded. ▪ She stood with her arms outstretched. = She stood with her arms wide open. ▪ She sat cradling the baby in her arms. ▪ I've known her since she was a babe in arms. [=a baby who is too young to walk and has to be held] ▪ He took her in/into his arms [=he embraced her] and kissed her passionately. ▪ She found him in the arms of [=being embraced by] another woman. ▪ He showed up at the party with a young woman on his arm. [=holding his arm] ▪ He took her (by the) arm and they walked in to dinner. — see picture at human 2 : the part of a piece of clothing (such as a shirt or coat) that covers the arm : sleeve
▪ The jacket's arms are too tight. = The jacket is too tight in the arms. 3 : a part of a piece of furniture (such as a chair or couch) that gives support for a person's arm
▪ the arm of the sofa — see also 1armchair 4 a : a long thin piece that is connected to the main part of a machine, structure, etc., and that looks or moves like a human arm
▪ the robot's mechanical arm ▪ the machine's robotic arm ▪ the arm of the record player
b : a long and narrow area of water
▪ an arm of the sea 5 : the part of a group or organization that performs a specific job or function — usually singular ▪ the organization's political arm [=the part of the organization that deals with politics] ▪ It is the most powerful arm [=division] of the organization. ▪ the military arm of the government 6 US, sports : a person's ability to throw a ball — usually singular ▪ Their pitcher's got a great arm. ▪ a strong/weak arm
▪ He has big, strong, muscular arms. ▪ She broke her left arm. = Her left arm was/got broken. ▪ He hurt his throwing/pitching arm [=the arm that he uses to throw/pitch a ball] in the last game. ▪ She put/threw her arms around him. [=she hugged him] ▪ She had a newspaper tucked under her arm. ▪ He was carrying a bag of groceries in each arm. ▪ He gave/offered his arm to her, and she took it. [=she held onto his arm] ▪ She grabbed my arm. = She grabbed me by the arm. ▪ He was standing there with his arms crossed/folded. ▪ She stood with her arms outstretched. = She stood with her arms wide open. ▪ She sat cradling the baby in her arms. ▪ I've known her since she was a babe in arms. [=a baby who is too young to walk and has to be held] ▪ He took her in/into his arms [=he embraced her] and kissed her passionately. ▪ She found him in the arms of [=being embraced by] another woman. ▪ He showed up at the party with a young woman on his arm. [=holding his arm] ▪ He took her (by the) arm and they walked in to dinner. — see picture at human
▪ The jacket's arms are too tight. = The jacket is too tight in the arms.
▪ the arm of the sofa — see also 1armchair
▪ the robot's mechanical arm ▪ the machine's robotic arm ▪ the arm of the record player
b : a long and narrow area of water
▪ an arm of the sea
an arm and a leg
informal : a very large amount of money
▪ It's a reliable car, and it doesn't cost an arm and a leg. [=it isn't too expensive]
▪ It's a reliable car, and it doesn't cost an arm and a leg. [=it isn't too expensive]
arm in arm
: next to each other with the arm of one person linked at the elbow to the arm of another person
▪ an elderly couple walking down the street arm in arm
▪ an elderly couple walking down the street arm in arm
a shot in the arm — see 1shot
as long as someone's arm — see 1long
at arm's length
: from a distance that is the length of a person's arm
▪ It's best to view the painting at arm's length. ▪ holding a candle at arm's length ◊To keep someone or something at arm's length is to avoid being very close to or friendly with someone or something.
▪ Since going to college, he has kept his old friends at arm's length. ▪ They no longer trust her and are keeping her at arm's length. ▪ The government has kept the group at arm's length until now.
▪ It's best to view the painting at arm's length. ▪ holding a candle at arm's length ◊To keep someone or something at arm's length is to avoid being very close to or friendly with someone or something.
▪ Since going to college, he has kept his old friends at arm's length. ▪ They no longer trust her and are keeping her at arm's length. ▪ The government has kept the group at arm's length until now.
chance your arm — see 2chance
give your right arm — see 1give
the long arm of the law
: the ability of the police to find and catch people who commit crimes
▪ The long arm of the law finally caught up with him [=the police caught him] 30 years later. ▪ So far, she's been able to escape the long arm of the law.
▪ The long arm of the law finally caught up with him [=the police caught him] 30 years later. ▪ So far, she's been able to escape the long arm of the law.
twist someone's arm — see 1twist
with open arms
: in a very kind and friendly way
▪ We were welcomed back with open arms.
▪ We were welcomed back with open arms.
— compare 2arm
