radioactinium
[ rey-dee-oh-ak-tin-ee-uhm ]
/ ˌreɪ di oʊ ækˈtɪn i əm /
noun Chemistry.
the radioactive isotope of thorium having a mass number 227 and a half-life of 18.8 days. Symbol: RdAc, Th 227
QUIZZES
THINK YOU’VE GOT A HANDLE ON THIS US STATE NICKNAME QUIZ?
Did you ever collect all those state quarters? Put them to good use on this quiz about curious state monikers and the facts around them.
Question 1 of 8
Mississippi’s nickname comes from the magnificent trees that grow there. What is it?
Words nearby radioactinium
Radiguet, radii, Radin, radio, radioacoustics, radioactinium, radioactivate, radioactive, radioactive constant, radioactive dating, radioactive decay
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020