Arm meaning : The portion of the upper human appendage, from the shoulder to the wrist and sometimes including the hand. The extended portion of the upper limb, from the shoulder to the elbow. A limb, or locomotive or prehensile organ, of an invertebrate animal. A long, narrow, more or less rigid part of an object extending from the main part or centre of the object, such as the arm of an armchair, a crane, a pair of spectacles or a pair of compasses. A bay or inlet off a main body of water. A branch of an organization. Power; might; strength; support. A pitcher One of the two parts of a chromosome. A group of patients in a medical trial. To take by the arm; to take up in one's arms.