nucleus: Meaning and Definition of
Pronunciation: (n'klē-us, ny'-), [key]
— pl. -cle•i -cle•us•es.
- a central part about which other parts are grouped or gathered; core: A few faithful friends formed the nucleus of the club.
- a specialized, usually spherical mass of protoplasm encased in a double membrane, and found in most living eukaryotic cells, directing their growth, metabolism, and reproduction, and functioning in the transmission of genic characters. See illus. under
- the positively charged mass within an atom, composed of neutrons and protons, and possessing most of the mass but occupying only a small fraction of the volume of the atom.
- a mass of nerve cells in the brain or spinal cord in which nerve fibers form connections.
- Also calleda particle upon which condensation of water vapor occurs to form water drops or ice crystals.
- a fundamental arrangement of atoms, as the benzene ring, that may occur in many compounds by substitution of atoms without a change in structure.
- the condensed portion of the head of a comet.
- the central, most prominent segment in a syllable, consisting of a vowel, diphthong, or vowellike consonant, as the a-sound in cat or the l-sound in bottled; peak.
- the most prominent syllable in an utterance or stress group; tonic syllable.
- nucleus (Thesaurus)