adiactinic

[ ey-dahy-ak-tin-ik ]
/ ˌeɪ daɪ ækˈtɪn ɪk /

adjective

(of a medium) not capable of transmitting actinic rays.

Origin of adiactinic

First recorded in 1875–80; a-6 + diactinic

British Dictionary definitions for adiactinic

adiactinic
/ (ˌædɪækˈtɪnɪk) /

adjective

physics denoting a substance that does not transmit radiation affecting photochemically sensitive materials, such as a safelight in a photographic darkroom