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

  • n. An artificially produced radioactive element with atomic number 109 whose most long-lived isotopes have mass numbers of 266 and 268 with half-lives of 3.4 milliseconds and 70 milliseconds, respectively. Also called unnilennium. See Table at element.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A transuranic chemical element (symbol Mt) with atomic number 109.

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

  • n. a radioactive transuranic element


After Lise Meitner.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Named for Lise Meitner (Wiktionary)


  • First, we learn about the brave physicist after whom meitnerium is named.

    Women in Chemistry @ Chemical Heritage Foundation

  • An element discovered in 1982 has been named meitnerium to honor Lise Meitner (1878-1968), the Austrian-Swedish physicist and mathematician who discovered the element protactinium and made major contributions to the understanding of nuclear fission.



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