Definitions of nucleus

  1. a part of the cell containing DNA and RNA and responsible for growth and reproduction
  2. a small group of indispensable persons or things; " five periodicals make up the core of their publishing program"
  3. any histologically identifiable mass of neural cell bodies in the brain or spinal cord
  4. the positively charged dense center of an atom
  5. The body or the head of a comet.
  6. An incipient ovule of soft cellular tissue.
  7. A whole seed, as contained within the seed coats.
  8. 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.
  9. The tip, or earliest part, of a univalve or bivalve shell.
  10. The central part around which additional growths are added, as of an operculum.
  11. A visceral mass, containing the stomach and other organs, in Tunicata and some mollusks.
  12. 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.
  13. The kernel; the central part about which matter collects; the small, central mass of life- containing substance, from which plants and animals grow.
  14. The central mass round which matter gathers: ( astr.) the head of a comet:- pl. NUCLEI.
  15. Any central mass; head of a comet.
  16. A center of development; central mass, as of a comet; kernel.
  17. Central part of a body round which the rest accumulates; the body of a comet.
  18. Anything round which matter has accumulated; that which may form the solid foundation or basis, as the nucleus of an army; the solid centre of any nodule or rounded mass; the central fleshy part of an oval; the body of a comet.
  19. A complex spheroidal mass essential to the life of a cell.