Definition of greyout in US English:

greyout

(also grayout)

noun

  • Partial or incipient blackout experienced by a person subjected to strong accelerative forces, especially during flying; (more generally) momentary diminution of vision or consciousness, or partial loss of memory.

Origin

1940s; earliest use found in The Richmond Times-Dispatch. From to grey out, after blackout.

Pronunciation

greyout

/ˈɡreɪaʊt/