1. (n.) 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.

2. (n.) The body or the head of a comet.

3. (n.) An incipient ovule of soft cellular tissue.

4. (n.) A whole seed, as contained within the seed coats.

5. (n.) A body, usually spherical, in a cell or a protozoan, distinguished from the surrounding protoplasm by a difference in irrefrangibility 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.

6. (n.) The tip, or earliest part, of a univalve or bivalve shell.

7. (n.) The central part around which additional growths are added, as of an operculum.

8. (n.) A visceral mass, containing the stomach and other organs, in Tunicata and some mollusks.

Anlage Kern NMR alpha particle antibaryon antilepton antimeson atomic nucleus atomic particle axiom axis baryon basichromatin beta particle bud center center of action center of gravity centroid centrum chromatin chromatin strands core dead center diameter diaphragm egg electron elementary particle elixir embryo epicenter equator essence essential flower focus fundamental germ germen gist gravamen heart heterochromatin hub hypostasis inner essence interior karyosome karyotin kernel lepton loins macronucleus marrow mean meat median medulla meganucleus meson metacenter micronucleus middle midmost midriff midst nave navel neutron nub nuclear force nuclear magnetic resonance nuclear particle nuclear resonance nucleolus nucleon nucleosynthesis nuts and bolts omphalos ovum photon pith pivot plasmosome postulate principle proton quid quiddity quintessence rudiment sap seed soul spark spermatozoon spirit storm center strangeness strong interaction stuff substance the nitty-gritty thick thick of things triton umbilicus valence electron waist waistline zone