Ra″di‐ant, n. 1. (Opt.) The luminous point or object from which light emanates; also, a body radiating light brightly.
2. (Geom.) A straight line proceeding from a given point, or fixed pole, about which it is conceived to revolve.
3. (Astron.) The point in the heavens at which the apparent paths of shooting stars meet, when traced backward, or whence they appear to radiate.