am·​er·​i·​ci·​um | \ ˌa-mə-ˈri-shē-əm How to pronounce americium (audio) , -sē-\

Definition of americium

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

Examples of americium in a Sentence

Recent Examples on the Web

The waste includes isotopes of iodine, strontium, americium, plutonium, uranium and other unstable elements, many of which are toxic as well as radioactive. Ralph Vartabedian,, "Nuclear waste will be classified as safer under a controversial Trump administration change," 5 June 2019 Inhalation of the particles, which included uranium, thorium, plutonium and americium, can increase the risk of cancer. Hal Bernton, The Seattle Times, "Study: Traces of radioactive contamination found in homes of six Hanford workers," 14 June 2018 Heavier elements are also created in a reactor core when uranium that hasn't been fissioned captures neutrons (plutonium and americium are two of these). Andrew Karam, Popular Mechanics, "Five Years Later, Cutting Through the Fukushima Myths," 11 Mar. 2016 State monitoring has found that plutonium and americium particles traveled as far as 10 miles from the demolition site, near Richland. Annette Cary, The Seattle Times, "42 Hanford workers contaminated with radiation," 24 Mar. 2018 Outside the body, small bits of americium pose almost no threat to human health. Patrick Malone And Peter Cary, idahostatesman, "Unheeded warnings, repeated mistakes put lives at risk at Idaho nuclear lab," 10 Aug. 2017 While in his bedroom, devices used by police bomb technicians alerted to the presence of radiation sources — thorium and americium. David Goodhue, miamiherald, "Admitted neo-Nazi stopped in Keys wanted for making explosives at home, cops say," 22 May 2017 The criminal complaint says those were thorium and americium, both radioactive metals. Dan Sullivan, miamiherald, "'Neo-Nazi' aimed to hit Turkey Point nuclear plant, Tampa murder suspect tells police," 14 June 2017 Power would come from a tiny radioactive source like americium, the element in smoke detectors. Dennis Overbye, New York Times, "Reaching for the Stars, Across 4.37 Light-Years," 12 Apr. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'americium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of americium

1946, in the meaning defined above

History and Etymology for americium

New Latin, from America + New Latin -ium

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Statistics for americium

Last Updated

22 Jun 2019

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Time Traveler for americium

The first known use of americium was in 1946

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am·​er·​i·​ci·​um | \ ˌam-ə-ˈris(h)-ē-əm How to pronounce americium (audio) \

Medical Definition of americium

: a radioactive metallic element produced by bombardment of plutonium with high-energy neutrons symbol Am — see Chemical Elements Table

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