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actinide

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noun ac·ti·nide \ˈak-tə-ˌnīd\

Definition of actinide

  1. :  any of the series of elements with increasing atomic numbers that begins with actinium or thorium and ends with lawrencium — see periodic table table



Origin of actinide

International Scientific Vocabulary


First Known Use: 1945


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a timid, meek, or unassertive person

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