see the periodic table of elements in the Reference Supplement
, grayish, radioactive, metallic chemical element, one of the actinides, found in
monazite and thorite: it is used in magnesium alloys, the making of gas mantles, electronic
equipment, etc., and as a nuclear fuel
: symbol, Th; at. no., 90
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
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