Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 232 to 247. Am-241 and Am-243 are the isotopes with the longest half-lifes (432.2 years and 7,370 years, respectively), and are alpha-ray and gamma-ray emitters used as radiation sources in research, radiography, and smoke alarms. Atomic number 95; melting point 1176°C; boiling point 2011°C; specific gravity 12; valence 3, 4, 5, 6. cross-reference: Periodic Table.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun The chemical element (symbol Am) with an atomic number of 95.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a radioactive transuranic metallic element; discovered by bombarding uranium with helium atoms

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[After America.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Americ(as) + -ium, by analogy with europium.

Examples

  • Barot wrote a letter to the leaders of al-Qaeda proposing that he would mine the small amount of radioactive material known as americium that can be found in ordinary smoke detectors and use it to build a radiological device.

    The Longest War

  • Barot wrote a letter to the leaders of al-Qaeda proposing that he would mine the small amount of radioactive material known as americium that can be found in ordinary smoke detectors and use it to build a radiological device.

    The Longest War

  • Barot wrote a letter to the leaders of al-Qaeda proposing that he would mine the small amount of radioactive material known as americium that can be found in ordinary smoke detectors and use it to build a radiological device.

    The Longest War

  • Barot wrote a letter to the leaders of al-Qaeda proposing that he would mine the small amount of radioactive material known as americium that can be found in ordinary smoke detectors and use it to build a radiological device.

    The Longest War

  • Smoke detectors, he learned, contain small amounts of a radio-active element called americium, while camping lanterns contain thorium.

    CNN.com

  • Hahn diligently amassed this radioactive material by collecting small amounts from household products, such as americium from smoke detectors, thorium from camping lantern mantles, radium from clocks and tritium (as neutron moderator) from gun-sights.

    Greensboring® Greensboro, NC

  • Acord has therefore basically produced a conventional americium-beryllium neutron source from home-made materials.

    Archive 2009-04-01

  • In his presentation document to al-Qaeda, Barot said that the americium from around ten thousand smoke detectors would be needed to make the bomb effective and that once the device was detonated the subsequent radioactive cloud “has the potential to affect around 500 people.”

    The Longest War

  • In his presentation document to al-Qaeda, Barot said that the americium from around ten thousand smoke detectors would be needed to make the bomb effective and that once the device was detonated the subsequent radioactive cloud “has the potential to affect around 500 people.”

    The Longest War

  • In his presentation document to al-Qaeda, Barot said that the americium from around ten thousand smoke detectors would be needed to make the bomb effective and that once the device was detonated the subsequent radioactive cloud “has the potential to affect around 500 people.”

    The Longest War

Comments

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  • Am.

    December 16, 2007