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plutonium definition

☆ plu·to·nium (plo̵̅o̅ tō′nē əm)

noun

a radioactive, metallic chemical element, one of the actinides, found in trace quantities in native uranium ores and produced by bombarding uranium with deuterons: symbol, Pu; at. no., 94: its most important isotope (plutonium-239) is used in nuclear weapons and as a reactor fuel

Etymology: ModL, after Pluto (planet) + -ium: so named (1942) by G. T. Glenn T(heodore) Seaborg, E. M. Edwin Mattison McMillan, A. C. Wahl (1917-2006), & J. W. Kennedy (1916-57), U.S. physicists who isolated it (1940), because next to neptunium, as Pluto comes next to Neptune

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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