Nucleus

1. n. A visceral mass, containing the stomach and other organs, in Tunicata and some mollusks.
2. n. A kernel; hence, a central mass or point about which matter is gathered, or to which accretion is made; the central or material portion; — used both literally and figuratively.
3. n. The body or the head of a comet.
4. n. An incipient ovule of soft cellular tissue.
5. n. A whole seed, as contained within the seed coats.
6. n. A body, usually spheroidal, in a cell or a protozoan, distinguished from the surrounding protoplasm by a difference in refrangibility and in behavior towards chemical reagents. It is more or less protoplasmic, and consists of a clear fluid (achromatin) through which extends a network of fibers (chromatin) in which may be suspended a second rounded body, the nucleolus (see Nucleoplasm). See Cell division, under Division.
7. n. The tip, or earliest part, of a univalve or bivalve shell.
8. n. The central part around which additional growths are added, as of an operculum.

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.