Nucleus

3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Nucleus \Nu"cle*us\, n.; pl. E. {Nucleuses}, L. {Nuclei}. [L., a
     kernel, dim. fr. nux, nucis, nut. Cf. {Newel} post.]
     [1913 Webster]
     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.
        [1913 Webster]
  
              It must contain within itself a nucleus of truth.
                                                    --I. Taylor.
        [1913 Webster]
  
     2. (Astron.) The body or the head of a comet.
        [1913 Webster]
  
     3. (Bot.)
        (a) An incipient ovule of soft cellular tissue.
        (b) A whole seed, as contained within the seed coats.
            [1913 Webster]
  
     4. (Biol.) A body, usually spheroidal, in a eukaryotic cell,
        distinguished from the surrounding protoplasm by a
        difference in refrangibility and in behavior towards
        chemical reagents, which contains the chromosomal genetic
        material, including the chromosomal DNA. 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}.
        [1913 Webster +PJC]
  
     Note: The nucleus is sometimes termed the endoplast or
           endoblast, and in the protozoa is supposed to be
           concerned in the female part of the reproductive
           process. See {Karyokinesis}.
           [1913 Webster]
  
     5. (Zool.)
        (a) The tip, or earliest part, of a univalve or bivalve
            shell.
        (b) The central part around which additional growths are
            added, as of an operculum.
        (c) A visceral mass, containing the stomach and other
            organs, in Tunicata and some mollusks.
            [1913 Webster]

From WordNet (r) 2.0 [wn]:

  nucleus
       n 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
       [also: {nuclei} (pl)]

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:

  112 Moby Thesaurus words for "nucleus":
     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