Meaning of “arm” - Learner’s Dictionary

arm

noun [ C ] uk us /ɑːm/
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)