D-Day
/ˈdiːdeɪ/noun
1- the day (6 June 1944) in the Second World War on which Allied forces invaded northern France by means of beach landings in Normandy进攻日（1944年6月6日, 二战时同盟国部队当天在诺曼底海滩登陆进入法国东部）。
1.1
- the day on which an important operation is to begin or a change to take effect计划开始日。
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