blackout (n.)

also black-out, 1908 in the theatrical sense of a darkened stage, from black (v.) + out (adv.). Figurative sense of "loss of memory" is 1934 (verb and noun); as "a dousing of lights as an air raid precaution," it is recorded from 1935. Verbal phrase black out, in reference to printed or written matter deemed objectionable and covered in black ink, is attested from 1888.