thorium
[thawr-ee-uh m, thohr-]
- a grayish-white, lustrous, somewhat ductile and malleable, radioactive metallic element present in monazite: used as a source of nuclear energy, as a coating on sun-lamp and vacuum-tube filament coatings, and in alloys. Symbol: Th; atomic weight: 232.038; atomic number: 90; specific gravity: 11.7.
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Origin of thorium
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for thorium
Contemporary Examples of thorium
He was also the person who first identified silicon, selenium, thorium, and serium.
Historical Examples of thorium
A million bucks of thorium with a hundred years of life in it—have a heart, mister!
The SyndicC.M. Kornbluth
The substance ranking next in radio-activity to radium is thorium.
Inventors at WorkGeorge Iles
Similar phenomena were observed when radium was substituted for thorium.
A Brief Account of Radio-activityFrancis Preston Venable
Thorium and uranium, proportionality of, in older rocks, 26.
The Birth-Time of the World and Other Scientific EssaysJ. (John) Joly
Emperor of all the metal molecules and king of the thorium spurs.
Rip Foster in Ride the Gray PlanetHarold Leland Goodwin
thorium
- a soft ductile silvery-white metallic element. It is radioactive and occurs in thorite and monazite: used in gas mantles, magnesium alloys, electronic equipment, and as a nuclear power source. Symbol: Th; atomic no: 90; atomic wt: 232.0381; half-life of most stable isotope, 232 Th: 1.41 × 10 10 years; valency: 4; relative density: 11.72; melting pt: 1755°C; boiling pt: 4788°C
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Word Origin for thorium
C19: New Latin, from Thor + -ium
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for thorium
rare metallic element, 1832, Modern Latin, named 1828-9 by its discoverer, Swedish chemist Jöns Jakob Berzelius (1779-1848) in honor of the Scandinavian god Thor.
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Online Etymology Dictionary, © 2010 Douglas Harper
thorium
(thôr′ē-əm)- A radioactive metallic element that is used in magnesium alloys; its longest-lived isotope, Th 232, has a half-life of 1.41 X 1010 years. Atomic number 90.
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The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
thorium
[thôr′ē-əm]
- A silvery-white, radioactive metallic element of the actinide series. It is used for fuel in some nuclear reactors and for improving the high-temperature strength of magnesium alloys. The only naturally occurring isotope of thorium, Th 232, is also its most stable, having a half-life of 14.1 billion years. Atomic number 90; atomic weight 232.038; approximate melting point 1,750°C; approximate boiling point 4,500°C; approximate specific gravity 11.7; valence 4. See Periodic Table.
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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.