Ra″di‐ant (–ant), a. [L. radians, -antis, p. pr. of radiare to emit rays or beams, fr. radius ray: cf. F. radiant. See Radius, Ray a divergent line.] 1. Emitting or proceeding as from a center; resembling rays; radiating; radiate.
2. Especially, emitting or darting rays of light or heat; issuing in beams or rays; beaming with brightness; emitting a vivid light or splendor; as, the radiant sun.
Mark what radiant state she spreads. Milton.
3. Beaming with vivacity and happiness; as, a radiant face.
4. (Her.) Giving off rays; — said of a bearing; as, the sun radiant; a crown radiant.
5. (Bot.) Having a raylike appearance, as the large marginal flowers of certain umbelliferous plants; — said also of the cluster which has such marginal flowers.
Radiant energy(Physics), energy given out or transmitted by radiation, as in the case of light and radiant heat. — Radiant heat, heat proceeding in right lines, or directly from the heated body, after the manner of light, in distinction from heat conducted or carried by intervening media. — Radiant point. (Astron.) See Radiant, n., 3.