d Meaning, Definition & Usage

  1. noun a fat-soluble vitamin that prevents rickets
    calciferol; viosterol; cholecalciferol; vitamin D; ergocalciferol.
  2. noun the cardinal number that is the product of one hundred and five
    five hundred; 500.
  3. noun the 4th letter of the Roman alphabet
  4. adjective satellite denoting a quantity consisting of 500 items or units
    five hundred; 500.

WordNet

D
Definitions
  1. The fourth letter of the English alphabet, and a vocal consonent. The English letter is from Latin, which is from Greek, which took it from Phoenician, 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. , Skr. duhitr. See Guide to Pronunciation
  2. (Mus.) 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. 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.

Webster 1913