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.-the body or the head of a comet.-an incipient ovule of soft cellular tissue.-a whole seed, as contained within the seed coats.-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.-the tip, or earliest part, of a univalve or bivalve shell.-the central part around which additional growths are added, as of an operculum.-a visceral mass, containing the stomach and other organs, in tunicata and some mollusks.