Try Our Apps
Dictionary.com

follow Dictionary.com

The Best Internet Slang

radioactive

[rey-dee-oh-ak-tiv] /ˌreɪ di oʊˈæk tɪv/
adjective, Physics, Chemistry.
1.
of, pertaining to, exhibiting, or caused by radioactivity.
Origin of radioactive
1895-1900
First recorded in 1895-1900; radio- + active
Related forms
radioactively, adverb
nonradioactive, adjective
unradioactive, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
Cite This Source
Examples from the Web for radioactive
Contemporary Examples
Historical Examples
  • But in order for radioactive breakdown to occur, time must pass.

    Equation of Doom

    Gerald Vance
  • "Eighty-five isn't nearly as radioactive as the elements akin to it," he said.

  • You see, the radioactive planets your men reported, one of them was—home.

    Alien Offer Al Sevcik
  • The hull was probably too radioactive to approach from the outside.

    The Lani People J. F. Bone
  • They said she was radioactive, but most of 'em wouldn't believe it.

    The Onslaught from Rigel Fletcher Pratt
British Dictionary definitions for radioactive

radioactive

/ˌreɪdɪəʊˈæktɪv/
adjective
1.
exhibiting, using, or concerned with radioactivity
Derived Forms
radioactively, adverb
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
Cite This Source
Word Origin and History for radioactive
adj.

1898, from French radio-actif, coined by Pierre and Marie Curie from radio-, comb. form of Latin radius (see radiation) + actif "active" (see active).

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
radioactive in Medicine

radioactive ra·di·o·ac·tive (rā'dē-ō-āk'tĭv)
adj.
Of or exhibiting radioactivity.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
radioactive in Culture

radioactive definition


A descriptive term for a material made up of atoms in which radioactivity occurs.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source

Word of the Day

Difficulty index for radioactive

Most English speakers likely know this word

Word Value for radioactive

17
19
Scrabble Words With Friends

Nearby words for radioactive