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radium A

American  

noun

Chemistry.

  1. a substance, formed by decay of radon, that gives rise to radium B.

Etymology

Origin of radium A

First recorded in 1900–05

Example Sentences

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Thus a zircon nucleus with a diameter of but 3.4 x 10-4 cms. formed a halo strongly darkened within, and showing radium A and radium C as clear smoky rings.

From The Birth-Time of the World and Other Scientific Essays by Joly, John

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.