[ rey-dee-uhnt ]
See synonyms for: radiantradiantly on Thesaurus.com

  1. emitting rays of light; shining; bright: the radiant sun;radiant colors.

  2. bright with joy, hope, etc.: radiant smiles;a radiant future.

  1. Physics. emitted or propagated by radiation.

  2. 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.

  1. a point or object from which rays proceed.

  2. Astronomy. the point in the heavens from which a shower of meteors appears to radiate.

  1. a refractory absorbing and radiating heat from the flames of a gas fireplace or the like.

Origin of radiant

First recorded in 1400–50; late Middle English, from Latin radiant-, stem of radiāns “shining,” present participle of radiāre “to radiate light, shine,” verb derivative of radius “beam, ray”; see radius

synonym study For radiant

1. See bright.

Other words for radiant

Opposites for radiant

Other words from radiant

  • ra·di·ant·ly, adverb
  • an·ti·ra·di·ant, adjective
  • non·ra·di·ant, adjective
  • non·ra·di·ant·ly, adverb
  • su·per·ra·di·ant, adjective
  • un·ra·di·ant, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use radiant in a sentence

British Dictionary definitions for radiant


/ (ˈreɪdɪənt) /

  1. sending out rays of light; bright; shining

  2. characterized by health, intense joy, happiness, etc: a radiant countenance

  1. emitted or propagated by or as radiation; radiated: radiant heat

  2. sending out heat by radiation: a radiant heater

  3. physics (of a physical quantity in photometry) evaluated by absolute energy measurements: radiant flux; radiant efficiency Compare luminous

  1. a point or object that emits radiation, esp the part of a heater that gives out heat

  2. astronomy the point in space from which a meteor shower appears to emanate

Origin of radiant

C15: from Latin radiāre to shine, from radius ray of light, radius

Derived forms of radiant

  • radiantly, 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

Scientific definitions for radiant


[ dē-ənt ]

  1. Transmitting light, heat, or other radiation. Stars, for example, are radiant bodies.

  2. Consisting of or transmitted as radiation.

  1. The apparent celestial origin of a meteor shower. For example, a point in the constellation Gemini is the radiant of the Geminid meteor shower.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.