[mahyt-nur-ee-uh m]

noun Chemistry, Physics.

a superheavy, synthetic, radioactive element. Symbol: Mt; atomic number: 109.

Nearby words

  1. meissonier,
  2. meissonier, jean louis ernest,
  3. meistersinger,
  4. meitner,
  5. meitner, lise,
  6. mek,
  7. meker burner,
  8. mekhitarist,
  9. mekka,
  10. meknès

Origin of meitnerium

named after Austrian physicist Lise Meitner;see -ium

Formerly unnilennium, element 109. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for meitnerium



a synthetic element produced in small quantities by high-energy ion bombardment. Symbol: Mt; atomic no: 109

Word Origin for meitnerium

C20: named after Lise Meitner

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for meitnerium




A synthetic, radioactive element that is produced by bombarding bismuth with iron ions. Its most long-lived isotopes have mass numbers of 266 and 268 with half-lives of 3.4 milliseconds and 70 milliseconds, respectively. Atomic number 109. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.