Boss

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

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.