noun \ˌa-mə-ˈri-shē-əm, -sē-\

Definition of AMERICIUM

:  a radioactive metallic element produced artificially by bombarding plutonium with high-energy neutrons — see element table


New Latin, from America + New Latin -ium
First Known Use: 1946


noun \ˌam-ə-ˈris(h)-ē-əm\   (Medical Dictionary)

Medical Definition of AMERICIUM

: a radioactive metallic element produced by bombardment of plutonium with high-energy neutrons—symbol Am; see element table


noun    (Concise Encyclopedia)

Synthetic radioactive chemical element, chemical symbol Am, atomic number 95. The fourth transuranium element discovered, it was first produced in 1944 from plutonium-239 in a nuclear reactor. The isotope americium-241 has been prepared in kilogram quantities and is used in a variety of measuring applications that utilize its gamma radiation. Its most familiar use is in household smoke detectors.


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Previous Word in the Dictionary: American yew
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