irradiation

UK: /ɪˌreɪdiˈeɪʃ^ən/ US: /ɪˌreɪdiˈeɪʃən/ ,(i rā′dē ā′shən)

WordReference Random House Unabridged Dictionary of American English © 2025

ir•ra•di•a•tion  (i rā′dē ā′shən), n. 

1. Physics the act of irradiating.
2. Physics the state of being irradiated.
3. intellectual or spiritual enlightenment.
4. a ray of light;
   beam.
5. [Optics.] the apparent enlargement of an object when seen against a dark background.
6. the use of x-rays or other forms of radiation for the treatment of disease, the making of x-ray photographs, the manufacture of vitamin D, etc.
7. Physics exposure or the process of exposure to x-rays or other radiation.
8. Physics irradiance.

• Late Latin irradiātiōn- (stem of irradiātiō). See ir-¹, radiation
• 1580–90

Collins Concise English Dictionary © HarperCollins Publishers::

irradiation / ɪˌreɪdɪˈeɪʃən/ noun

1. another name for radiation, irradiance

WordReference Random House Learner's Dictionary of American English © 2025

ir•ra•di•ate /v. ɪˈreɪdiˌeɪt; adj. -ɪt, -ˌeɪt/   v. [~ + object] , -at•ed, -at•ing, adj. 

1. to shed rays of light on;
   illuminate.
2. Physics to heat with radiant energy.
3. Physics to expose to radiation, as for medical treatment.

ir•ra•di•a•tion /ɪˌreɪdiˈeɪʃən/  n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

ir•ra•di•ate  (v. i rā′dē āt′;adj. i rā′dē it, -āt′), v., -at•ed, -at•ing, adj. 
v.t. 

1. to shed rays of light upon;
   illuminate.
2. to illumine intellectually or spiritually.
3. to brighten as if with light.
4. Physics to radiate (light, illumination, etc.).
5. Physics to heat with radiant energy.
6. Physics to treat by exposure to radiation, as of ultraviolet light.
7. Physics to expose to radiation.

v.i. 

8. [Archaic.]
   • to emit rays;
     shine.
   • to become radiant.

adj. 

9. irradiated;
   bright.

• Latin irradiātus, past participle of irradiāre to shine upon. See ir-¹, radiate
• 1595–1605

ir•ra′di•at′ing•ly, adv. 
ir•ra′di•a′tive, adj. 
ir•ra′di•a′tor, n.