radioactinium

noun ra·dio·actinium \"+\

Definition of radioactinium

  1. :  the radioactive isotope of thorium of mass number 227 formed by disintegration of actinium —symbol RdAc or Th227 — see actinium series

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Origin and Etymology of radioactinium

New Latin, from radio- + actinium


Seen and Heard

What made you want to look up radioactinium? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to cast off or become cast off

Get Word of the Day daily email!