/ diː; NAmE / noun , abbreviation , symbol
■ noun (also d ) [ C , U ] ( pl. Ds , D's , d's / diːz; NAmE /)
1.
the fourth letter of the English alphabet :
'Dog' begins with (a) D / 'D'.
2.
D ( music ) the second note in the scale of C major
3.
D the fourth highest mark / grade that a student can get for a piece of work, showing that it is not very good :
He got (a) D / 'D' in / for Geography.
—see also D-Day
■ abbreviation
(also D. especially in NAmE ) ( in politics in the US ) Democrat ; Democratic
■ symbol
the number 500 in Roman numerals