thorium
Use Thorium in a sentence
i noun Chemistry.
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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Based on the Random House Dictionary, © Random House, Inc. 2013.
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Link To thorium
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Thorium
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| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
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Collins
World English Dictionary
thorium (ˈθɔːrɪəm) ![[Click for IPA pronunciation guide]](http://static.sfdict.com/dictstatic/g/d/dictionary_questionbutton_default.gif) | |
| —n | |
| 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, 232Th: 1.41 × 1010 years; valency: 4; relative density: 11.72; melting pt: 1755°C; boiling pt: 4788°C | |
| [C19: New Latin, from | |
| 'thoric | |
| —adj | |
Collins English Dictionary - Complete & Unabridged 10th Edition
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2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline
Word Origin & History
thorium
rare metallic element, 1832, from Mod.L., named 1828-9 by its discoverer, Swed. chemist Jöns Jakob Berzelius (1779-1848) in honor of the Scand. god Thor (q.v.).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary
thorium tho·ri·um (thôr'ē-əm)
n.
Symbol Th
A radioactive metallic element that is used in magnesium alloys; its longest-lived isotope, Th 232, has a half-life of 1.41 × 1010 years. Atomic number 90; atomic weight 232.038; approximate melting point 1,750°C; approximate boiling point 4,800°C; approximate specific gravity 11.7; valence 4.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
| thorium (thôr'ē-əm) Pronunciation Key
Symbol Th 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. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Example sentences
Helium is a finite and increasingly scarce resource, produced extremely slowly by decaying uranium and thorium.
Thorium hardly gets a mention as a safer option, there is more thorium around than uranium.
She soon repeated the experiment with thorium, which behaved in similar ways.
Some refer to these variously as thorium salt reactors.
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