as a numeral d stands for 500. in this use it is not the initial of any word, or even strictly a letter, but one half of the sign / (or / ) the original tuscan numeral for 1000.
2. d ·- the nominal of the second tone in the model major scale (that in c), or of the fourth tone in the relative minor scale of c (that in a minor), or of the key tone in the relative minor of f.
3. d ·- the fourth letter of the english alphabet, and a vocal consonant. the english letter is from latin, which is from greek, which took it from ph/nician, the probable ultimate origin being egyptian. it is related most nearly to t and th; as, ·eng. deep, g. tief; ·eng. daughter, g. tochter, ·gr. qyga`thr, ·skr. duhitr. ·see guide to pronunciation, ?178, 179, 229.