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English definition of “nucleus”

nucleus

noun [C] uk   /ˈnjuː.kli.əs/ us    /ˈnuː-/ (plural nuclei or nucleuses)
specialized physics the central part of an atom, usually made up of protons and neutrons specialized biology the part of a cell that controls its growth: DNA is stored in the nucleus of a cell. the nucleus of sth the group of people or things that are the most important part of something: These three players will form the nucleus of a revised and stronger team.
(Definition of nucleus from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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