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Nucleus - Dictionary Definition and Overview |
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Nucleus : (noun)
1: a part of the cell containing DNA and RNA and responsible
for growth and reproduction [syn: cell nucleus, karyon]
2: the positively charged dense center of an atom
3: a small group of indispensable persons or things; "five
periodicals make up the core of their publishing program"
[syn: core, core group]
4: (astronomy) the center of the head of a comet; consists of
small solid particles of ice and frozen gas that vaporizes
on approaching the sun to form the coma and tail
5: any histologically identifiable mass of neural cell bodies
in the brain or spinal cord
Based on WordNet 2.0
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Nucleus : \Nu"cle*us\, 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.
Based on Webster's Revised Unabridged Dictionary
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Nucleus : Nucleus: 1) In cell biology, the structure that houses the chromosomes. 2) In neuroanatomy, a group of nerve cells.
Based on Webster's Revised Unabridged Dictionary (1913)
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