Meaning

noun a human limb; technically the part of the superior limb between the shoulder and the elbow but commonly used to refer to the whole superior limb

verb prepare oneself for a military confrontation

noun any projection that is thought to resemble a human arm

originFrom Middle English arm, from Old English earm (Anglian arm), from Proto-West Germanic *arm, from Proto-Germanic *armaz (“arm”), from Proto-Indo-European *h₂(e)rmos (“a fitting, joint; arm, forequarter”), a suffixed form of *h₂er-…

Etymology from Wiktionary, CC BY-SA 3.0