Emily Dickinson Lexicon

ARM, n. [Sax. arm, earm; D.G. Sw. Dan. arm; L. armus, an arm, a shoulder, a wing. In Russ. a shoulder is ramo, which may be the same word as the L. armus. If so, this word belongs to the root Rm coinciding with L. ramus, a branch, that is, a shoot, like the Celtic braich, L. brachium. But if the L. armus is directly from the Gr. ἁρμος, a joint, it would seem to be formed from Gr. αρω, to fit.]

1. The limb of the human body, which extends from the shoulder to the hand.
2. The branch of a tree, or the slender part of a machine, projecting from a trunk or axis. The limbs of animals are also sometimes called arms.
3. A narrow inlet of water from the sea.
4. Figuratively, power, might, strength; as, the secular arm. In this sense the word is often used in the Scriptures. To whom is the arm of the Lord revealed? Isa. liii.