1

actinoid

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adjective ac·ti·noid \ˈak-tə-ˌnȯid\

Definition of actinoid

  1. 1 :  resembling a ray especially of a radially symmetrical animal

  2. 2 :  exhibiting radial symmetry

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Origin and Etymology of actinoid

actin(ia) + 2-oid (probably after actinoida or actinoidea)


First Known Use: 1846


2

actinoid

play
noun ac·ti·noid \ˈak-tə-ˌnȯid\

Definition of actinoid

plural

actinoids

chemistry

  1. :  actinide The actinoid elements (or actinides; An) constitute a series of 14 elements which are formed by the progressive filling of the 5f electron shell and follow actinium in the periodic table (atomic numbers 90-103). — Mirtat Bouroushian, Electrochemistry of Metal Chalcogenides, 2010

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Origin and Etymology of actinoid

actin(ide) + 1-oid


First Known Use: 1958


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