Definition of D-notice in English:

D-notice

noun

British
  • A government notice issued to news editors requiring them not to publicize certain information for reasons of national security.

    ‘On 3 September, the Ministry of Defence issued a D notice about her case.’
    ‘That said you don't really have to silence everyone at an individual level you simply don't allow it into the mass media, in this country it's called a D notice.’

Origin

Second World War D for defence.

Pronunciation

D-notice