To send out rays or waves. To issue or emerge in rays or waves: Heat radiated from the stove. To extend in straight lines from or toward a center; diverge or converge like rays: Spokes radiate from a wheel hub. Ecology To spread into new habitats and thereby diverge or diversify. Used of a group of organisms. To emit (light, for example) in or as if in rays. To send or spread out from or as if from a center: a cactus that radiates spines. To irradiate or illuminate (an object). To manifest in a glowing manner: a leader who radiates confidence. Botany Having rays or raylike parts, as in the flower heads of daisies. Biology Characterized by radial symmetry. Surrounded with rays: a radiate head on a coin.