radium

[ rey-dee-uhm ]

noun
  1. Chemistry. a highly radioactive metallic element whose decay yields radon gas and alpha rays. Symbol: Ra; atomic weight: 226; atomic number: 88.

  2. a lustrous rayon or silk fabric constructed in plain weave and used in women's apparel, lining, and drapery.

Origin of radium

1
1895–1900; <New Latin, equivalent to Latin rad(ius) ray (see radius) + -ium-ium

Words Nearby radium

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use radium in a sentence

  • We know now that radium, or at least radio-active substances, represent the philosopher's stone of the olden time.

  • radium was discovered in 1898 by M. and Madame Curie and M. Bmont, while experimenting with the uranium mineral pitchblende.

    Invention | Bradley A. Fiske
  • It seems that an atom of radium does actually disintegrate, and by disintegrating give out energy.

    Invention | Bradley A. Fiske
  • "They are using radium repellent rays to keep us from approaching," he informed.

    The Jameson Satellite | Neil Ronald Jones
  • The cost of one pound of radium is variously estimated at from one to three millions of dollars.

British Dictionary definitions for radium

radium

/ (ˈreɪdɪəm) /


noun
    • a highly radioactive luminescent white element of the alkaline earth group of metals. It occurs in pitchblende, carnotite, and other uranium ores, and is used in radiotherapy and in luminous paints. Symbol: Ra; atomic no: 88; half-life of most stable isotope, 226 Ra: 1620 years; valency: 2; relative density: 5; melting pt: 700°C; boiling pt: 1140°C

    • (as modifier): radium needle

Origin of radium

1
C20: from Latin radius ray

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for radium

radium

[ dē-əm ]


Ra
  1. A rare, bright-white, highly radioactive element of the alkaline-earth group. It occurs naturally in very small amounts in ores and minerals containing uranium, and it is naturally luminescent. Radium is used as a source of radon gas for the treatment of disease and as a neutron source for scientific research. Its most stable isotope is Ra 226 with a half-life of 1,622 years. Atomic number 88; melting point 700°C; boiling point 1,737°C; valence 2. See Periodic Table.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for radium

radium

A naturally occurring radioactive chemical element. Its symbol is Ra.

Notes for radium

Radium was discovered by the chemists Marie and Pierre Curie.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.