D-day /'di: dei; 'di’de/ n (code name for the) day (6 June 1944) on which British and American forces landed in N France, during the Second World War; unnamed day on which important work is to start, 二次性界大戰(zhàn)時(shí)英美盟軍在法國(guó)北部登陸的 R 子 (1944 年 6 月 6 日); 該日的秘密代號(hào); 重大工作開(kāi)始之日。