Webster's Revised Unabridged Dictionary · 1913

black out

black out , intransitive verb

to experience a temporary loss of consciousness, memory, or vision.

black out , transitive verb

1.
to cause to become black, such as a stage, a computer screen, or a city.
2.
to impose a blackout on (news or a sports event).
3.
to make (a written text) illegible by applying a black ink over it; to blot out.
4.
to suppress (a memory).