Boss

1. To ornament with bosses; to stud.
2. Any protuberant part; a round, swelling part or body; a knoblike process; as, a boss of wood.
3. A master workman or superintendent; a director or manager; a political dictator.
4. A head or reservoir of water.
5. A projecting ornament placed at the intersection of the ribs of ceilings, whether vaulted or flat, and in other situations.
6. A swage or die used for shaping metals.
7. 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.
8. The enlarged part of a shaft, on which a wheel is keyed, or at the end, where it is coupled to another.
9. 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.