N-VAR 英语字母表的第 4 个字母 D is the fourth letter of the English alphabet.
N-VAR C 大调音阶中的第二音;D 音 In music, D is the second note in the scale of C major.
N-VAR (作业、考试成绩等的)丁等，D等，差 If you get a D as a mark for a piece of work or in an exam, your work is below average or poor.
I got a D+.
(用于墓碑上或工具书中等的日期前) d. is an abbreviation for (缩略=) died when it is written in front of dates, for example on graves or in reference books.
(英国1971年前使用的旧制辅币) d was a written abbreviation for (书面缩略=)penny or pence in Britain before decimal currency was introduced in 1971.
(用于首字母为 d 的一些单词的缩写，如 day, defeated或district） D or d is used as an abbreviation for words beginning with d, such as 'day', 'defeated', or 'district'.