D-notice
noun [ C usually singular ] uk/ˈdiːˌnəʊ.tɪs/ us/ˈdiːˌnoʊ.t̬ɪs/
国防机密通知（指英国政府为了国家要求某些消息不予以公开的命令）
a British government instruction preventing particular information from being made public in order to protect the country
The D-notice was lifted after news of the computer theft was circulated by an international news agency. 国防机密通知在一家国际通讯社对此次计算机失窃事件进行报道后被撤销了。