boss

n.; pl. Bosses [ OE. boce, bose, boche, OF. boce, boche, bosse, F. bosse, of G. origin; cf. OHG. bōzo tuft, bunch, OHG. bōzan, MHG. bôzen, to beat. See Beat, and cf. Botch a swelling. ] 1. Any protuberant part; a round, swelling part or body; a knoblike process; as, a boss of wood. [ 1913 Webster ]

2. A protuberant ornament on any work, either of different material from that of the work or of the same, as upon a buckler or bridle; a stud; a knob; the central projection of a shield. See Umbilicus. [ 1913 Webster ]

3. (Arch.) A projecting ornament placed at the intersection of the ribs of ceilings, whether vaulted or flat, and in other situations. [ 1913 Webster ]

4. [ Cf. D. bus box, Dan. bösse. ] A wooden vessel for the mortar used in tiling or masonry, hung by a hook from the laths, or from the rounds of a ladder. Gwilt. [ 1913 Webster ]

5. (Mech.) (a) The enlarged part of a shaft, on which a wheel is keyed, or at the end, where it is coupled to another. (b) A swage or die used for shaping metals. [ 1913 Webster ]

6. A head or reservoir of water. [ Obs. ] [ 1913 Webster ]