roentgenium

[ rent-gen-ee-uh m, -jen-, ruhnt- ]
/ rɛntˈgɛn i əm, -ˈdʒɛn-, rʌnt- /

noun Chemistry, Physics.

a superheavy, synthetic radioactive element with a very short half-life. Symbol: Rg; atomic number: 111.

Origin of roentgenium

named after German physicist Wilhelm Konrad Roentgen; see -ium
Formerly unununium, element 111.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019