English▸ adjective
1 sending out light; shining or glowing brightly:
a bird with radiant green and red plumage.
▪ (of a person or their expression) clearly emanating great joy, love, or health:
she gave him a radiant smile.
▪ (of an emotion or quality) emanating powerfully from someone or something; very intense or conspicuous:
he praised her radiant self-confidence.
2 [attributive] (of heat) transmitted by radiation, rather than conduction or convection:
plants convert the radiant energy of the sun into chemical energy.
▪ (of an appliance) designed to emit radiant energy, especially for cooking or heating:
a radiant heater.
▸ noun a point or object from which light or heat radiates, especially a heating element in an electric or gas heater:
I sat down by my hissing gas fire—one of the radiants was missing.
– ORIGIN late Middle English : from Latin radiant- ‘emitting rays’, from the verb radiare (see radiate).