[yoo-nil-sep-tee-uh m]

Origin of unnilseptium

< Latin ūn(us) one + nīl nothing + sept(em) seven + New Latin -ium -ium
Also called element 107.


[bawr-ee-uh m, bohr-]
noun Chemistry, Physics.
  1. a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Bh; atomic number: 107.

Origin of bohrium

named after Danish physicist Niels Bohr; see -ium
Formerly unnilseptium, element 107.

element 107

noun Chemistry, Physics.
  1. bohrium.

Origin of element 107

First recorded in 1975–80
Formerly unnilseptium.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for unnilseptium


  1. a transuranic element artificially produced in minute quantities by bombarding 204 Bi atoms with 54 Cr nuclei. Symbol: Bh; atomic no: 107Former names: element 107, unnilseptium

Word Origin for bohrium

C20: after Neils Bohr
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

unnilseptium in Science


  1. A synthetic, radioactive element that is produced by bombarding bismuth with chromium ions. Its most long-lived isotopes have mass numbers of 261, 262, and 264 with half-lives of 11.8 milliseconds, 0.1 second, and 0.44 second, respectively. Atomic number 107. See Periodic Table.
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