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(), n.; pl. E. Nucleuses (), L. Nuclei (). [L., a kernel, dim. fr. nux, nucis, nut. Cf. Newel post.] 1. 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. It must contain within itself a nucleus of truth. I. Taylor. 2. (Astron.) The body or the head of a comet. 3. (Bot.) (a) An incipient ovule of soft cellular tissue. (b) A whole seed, as contained within the seed coats. 4. (Biol.) 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 nucleus is sometimes termed the endopl スポンサード リンク
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