Definition of radiation
1a : the action or process of radiatingb : the process of emitting radiant energy in the form of waves or particlesc (1) : the combined processes of emission, transmission, and absorption of radiant energy (2) : the transfer of heat by radiation — compare conduction, convection
2a : something that is radiatedb : energy radiated in the form of waves or particles
3 : radial arrangement
radiationalplay \-shnəl, -shə-nəl\ adjective
radiationlessplay \-shən-ləs\ adjective
radiativeplay \ˈrā-dē-ˌā-tiv\ adjective
Examples of radiation in a Sentence
She was exposed to high levels of radiation.
He goes in for radiation next week.
the sun's radiation of heat
Recent Examples of radiation from the Web
Patients typically undergo surgery first to remove as much of the tumor as possible, then are treated with radiation and chemotherapy to slow the growth of any remaining malignant cells that cannot be removed.
Biden, the former vice president's oldest son and the attorney general for the state of Delaware, was diagnosed in 2013 and had surgery, radiation and chemotherapy before going back to work.
The results of the nation’s first major study comparing mastectomy with tumor removal and radiation were published in the New England Journal of Medicine in 1985.
Unlike other types of electromagnetic radiation, radio waves can pass through gas and dust over large distances of space without being absorbed or interrupted.
Christine’s husband had insurance that allowed her to undergo radiation treatment in Casablanca after her tumor was successfully removed by surgery in Senegal in November.
Even internal injuries are now treated here, including the late effects of radiation, osteomyelitis, and crush injuries.
Americans feared that radiation leaks would harm legions of people.
Sometimes the patients - on their way to doctor's appointments, chemotherapy or radiation treatments or support group meetings, or to pick up prescriptions - seek her out at her station just inside the automatic door.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radiation.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use of radiation
RADIATION Defined for English Language Learners
Definition of radiation for English Language Learners
: a type of dangerous and powerful energy that is produced by radioactive substances and nuclear reactions
medical : the use of controlled amounts of radiation for the treatment of diseases (such as cancer)
: energy that comes from a source in the form of waves or rays you cannot see
RADIATION Defined for Kids
Definition of radiation for Students
1 : the process of giving off energy in the form of waves or particles
2 : something that is radiated (as light or X-rays)
Medical Definition of radiation
1: energy radiated in the form of waves or particles
2a: the action or process of radiating with radiation of the pain there may be tenderness over the sciatic nerve—J. A. Keyb (1): the process of emitting radiant energy in the form of waves or particles (2): the combined processes of emission, transmission, and absorption of radiant energy
3: a tract of nerve fibers within the brain; especially : one concerned with the distribution of impulses arising from sensory stimuli to the relevant coordinating centers and nuclei the optic radiations
Seen and Heard
What made you want to look up radiation? Please tell us where you read or heard it (including the quote, if possible).