'americium' definitions:

Definition of 'americium'

From: WordNet
noun
A radioactive transuranic metallic element; discovered by bombarding uranium with helium atoms [syn: americium, Am, atomic number 95]

Definition of 'americium'

From: Elements
  • Symbol: Am
  • Atomic number: 95
  • Atomic weight: (243)
  • Radioactive metallic transuranic element, belongs to the actinoids. Ten known isotopes. Am-243 is the most stable isotope, with a half-life of 7.95*10^3 years. Discovered by Glenn T. Seaborg and associates in 1945, it was obtained by bombarding uranium-238 with alpha particles.