Origin: 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
See plutonium in American Heritage Dictionary 4
noun Symbol Pu
Origin: After the dwarf planet Pluto (from the fact that it follows neptunium in the periodic table).
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