Radiant beauty or splendour; lustre. In later use figurative: influence, especially cultural or intellectual; (cultural) diffusion.
Chiefly in French contexts or in translations from French.
Early 20th century; earliest use found in Wyndham Lewis (1882–1957), artist and writer. From French rayonnement emission of luminous rays, (of a person's face, etc.) radiance, influence from rayonner + -ment.