Meaning of “arm” - Learner’s Dictionary

arm

noun [ C ] us uk /ɑːm/
He grabbed my arm and pulled me away.Gerry slipped on the ice and broke his arm.He was carrying a package under his arm.He put his arm around her.I've got all these scratches on my arm from the cat.
BODY PART

A1 the long part at each side of the human body, ending in a hand:

She held the tiny baby in her arms.
He put his arms around her.
She was standing with her arms folded (= with one arm crossed over the other).
arm in arm

with your arm gently supporting or being supported by someone else's arm:

They walked through the park, arm in arm.
CLOTHES

the part of a piece of clothing that you put your arm in

CHAIR

the part of a chair where your arm rests

(Definition of “arm noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)