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. (Zo["o]l.) (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]

The Collaborative International Dictionary of English. 2000.


Look at other dictionaries:

  • nucléus — [ nykleys ] n. m. • 1864; « nucelle » 1846; du lat. nucleus ♦ Préhist. Noyau de silex ou autre roche dure, dont on extrait des éclats, des lames. ● nucléus ou nucleus nom masculin invariable Petit fragment, d origine biologique ou détritique, qui …   Encyclopédie Universelle

  • Nucleus — may refer to: Nucleus (atomic structure), the very dense region at the center of an atom Cell nucleus, the control center of a cell, which contains the cell s chromosomal DNA Nucleus (neuroanatomy), a cluster of neurons in the central nervous… …   Wikipedia

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  • Nucleus — (lat. „Kern“), selten Nukleus, steht für Atomkern, den massetragenden Teil im Zentrum eines Atoms Nucleus (ZNS), eine Ansammlung von Zellkörpern im Zentralnervensystem Silbenkern, eine Gruppe von Lauten im natürlichen Sprechfluss Zellkern, ein… …   Deutsch Wikipedia

  • nucleus — (n.) 1704, kernel of a nut, 1708, head of a comet, from L. nucleus kernel, from nucula little nut, dim. of nux (gen. nucis) nut, from PIE *kneu nut (Cf. M.Ir. cnu, Welsh cneuen, M.Bret. knoen nut, O.N …   Etymology dictionary

  • nucleus — [no͞o′klē əs, nyo͞o′klē əs] n. pl. nuclei [no͞o′klēī΄, nyo͞o′klēī΄] or nucleuses [ModL < L, a nut, kernel, for nuculeus, dim. < nux (gen. nucis), NUT] 1. a thing or part forming the center around which other things or parts are grouped or… …   English World dictionary

  • nucleus — nucleus. См. мужской пронуклеус. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • nucleus — nucleus. См. ядро. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Nucleus — Nucleus. См. Ядро. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

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