[yoo-nil-kwod-ee-uh m]

Origin of unnilquadium

1975–80; < Latin ūn(us) one + nīl nothing + quad(ri)- + New Latin -ium -ium
Also called element 104.


[ruhth-er-fawr-dee-uh m, -fohr-, ruhth-]
noun Chemistry, Physics.
  1. a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Rf; atomic number: 104.

Origin of rutherfordium

1969; named after English physicist Ernest Rutherford; see -ium
Formerly unnilquadium, element 104.

element 104

noun Chemistry, Physics.
  1. rutherfordium.

Origin of element 104

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

British Dictionary definitions for unnilquadium


  1. a transactinide element produced by bombarding californium-249 nuclei with carbon-12 nuclei. Symbol: Rf; atomic number.: 104; atomic wt: 261Name in the former Soviet Union: kurchatovium

Word Origin for rutherfordium

C20: named after Ernest Rutherford
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

unnilquadium in Science


  1. A synthetic, radioactive element that is produced by bombarding plutonium with carbon or neon ions. Its most stable isotope is Rf 261 with a half-life of 62 seconds. Atomic number 104. See Periodic Table.
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