radiant

UK: /ˈreɪdiənt/ US: /ˈreɪdiənt/ ,(rā′dē ənt)

WordReference Random House Learner's Dictionary of American English © 2026

ra•di•ant /ˈreɪdiənt/   adj. 

1. [before a noun] giving off rays of light;
   shining;
   bright.
2. bright with joy, hope, etc.:
   a radiant smile.
3. Physics given off or sent out by radiation:
   [before a noun] radiant energy; radiant heat.

ra•di•ant•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2026

ra•di•ant  (rā′dē ənt), adj. 

1. emitting rays of light;
   shining;
   bright:
   the radiant sun; radiant colors.
2. bright with joy, hope, etc.:
   radiant smiles; a radiant future.
3. Physics emitted or propagated by radiation.
4. Heraldry
   • noting a partition line having a series of flamelike indentations formed by ogees joined in zigzags;
     rayonny.
   • (of a charge, as an ordinary) having an edge or edges so formed.

n. 

5. a point or object from which rays proceed.
6. Astronomy the point in the heavens from which a shower of meteors appears to radiate.
7. Energy a refractory absorbing and radiating heat from the flames of a gas fireplace or the like.

• Latin radiant- (stem of radiāns, present participle of radiāre to radiate light, shine), equivalent. to radi(us) beam, ray (see radius) + -ant- -ant
• late Middle English 1400–50

ra′di•ant•ly, adv. 
Synonyms

• 1. beaming, refulgent, resplendent. See bright. 

Antonyms

• 1. dim.

Collins Concise English Dictionary © HarperCollins Publishers::

radiant / ˈreɪdɪənt/ adjective

1. sending out rays of light; bright; shining
2. characterized by health, intense joy, happiness, etc
3. emitted or propagated by or as radiation; radiated: radiant heat
4. sending out heat by radiation: a radiant heater
5. (of a physical quantity in photometry) evaluated by absolute energy measurements: radiant flux, radiant efficiency
   Compare luminous

noun

1. a point or object that emits radiation, esp the part of a heater that gives out heat
2. the point in space from which a meteor shower appears to emanate

Etymology: 15th Century: from Latin radiāre to shine, from radius ray of light, radius

ˈradiantly adverb