Emily Dickinson Lexicon

BOSS, n. [Fr. bosse; Arm. boçz. In D. bos is a bunch, a bundle, a truss, a tuft, a bush, a sheaf, whence bosch, G. busch, a bush or thicket. In W. bôth is the boss of a buckler, the nave of a wheel, and a bottle, and hence W. bothel, a rotundity, a bottle or any round vessel, a wheal or blister. A boss is a protuberance, either from shooting, projecting, or from collecting and forming a mass.]

1. A stud or knob; a protuberant ornament, of silver, ivory, or other material, used on bridles, harness, &c.
2. A protuberant part; a prominence; as, the boss of a buckler.
3. A round or swelling body of any kind; as, a boss of wood. – Moxon.
4. A water-conduit, in form of a tun-bellied figure. – Ash. Bailey.