radioactive

play

adjective ra·dio·ac·tive \ ˌrā-dē-ō-ˈak-tiv \

Definition of radioactive

:of, caused by, or exhibiting radioactivity

—

radioactively

adverb

See radioactive defined for English-language learners

See radioactive defined for kids

Examples of radioactive in a Sentence

Uranium and plutonium are radioactive.

Recent Examples of radioactive from the Web

The original decision to accumulate hundreds of tons of highly radioactive waste in Idaho was driven by a desire, as an admiral once told me, to keep the material out of sight and out of mind.

— rocky barker, idahostatesman, "Andrus’ legacy: Idaho’s wild spaces, schools, nuclear cleanup," 25 Aug. 2017
The region might also face environmental threats should the U.S. strike Kim’s heavy-water reactor north of the capital Pyongyang, scattering radioactive debris into the atmosphere and groundwater.

— brendan scott, Bloomberg.com, "A Second Korean War Could Quickly Spread Across All of Asia," 21 Aug. 2017
There was nothing wrong with my womb; a doctor shot radioactive dye in it to check.

— joanna petrone, Longreads, "Pregnant, then Ruptured," 18 Aug. 2017
Those radioactive molecules get bound up in living matter, like trees.

— ben panko, Smithsonian, "This New Mexico Petroglyph Might Reveal an Ancient Solar Eclipse," 17 Aug. 2017
To prevent radioactive material from spreading, people should remove their outer clothing, seal it in a plastic bag and get as far away as possible, the fact sheet says.

— andrew degrandpre, chicagotribune.com, "Guam releases guidance to prepare residents for North Korean nuclear strike," 11 Aug. 2017
The day care center and a school in the area were investigated for radioactive contamination but were ultimately not included in the Superfund designation.

— vivian wang, New York Times, "It’s a Superfund Site, but It’s Also Their Livelihood," 4 Aug. 2017
And it could be accomplished by mathematically calculating the radioactive decay of isotopes into atoms of lead.

— ed wallace, star-telegram, "Get the lead out," 28 July 2017
The Hanford site, in southeastern Washington State, is the source of a plume of radioactive sludge that has contaminated the ground water and is creeping toward the Columbia River.

— graydon carter, The Hive, "Donald Trump’s High-Risk, Low-Energy Nightmare," 26 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radioactive.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.