D (minuscule: d) is the fourth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide.

d, letter that has retained the fourth place in the alphabet from the earliest point at which it appears in history. It corresponds to Semitic daleth and Greek delta (Δ). The form is thought to derive from an …

Define D. D synonyms, D pronunciation, D translation, English dictionary definition of D. 1. The symbol for the isotope deuterium. 2. also d The symbol for the Roman numeral 500. abbr. 1. dative 2. day 3. …

'D definition: contraction of had: See examples of 'd used in a sentence.

3 days ago · The letter d is used in the alphabets of many languages, and in several romanization systems of non-Latin scripts to represent the voiced alveolar or dental plosive (/d/). In some …

D, d meaning: 1. the fourth letter of the English alphabet 2. the sign used in the Roman system for the number…. Learn more.

the 4th letter of the Roman alphabet "D." Vocabulary.com Dictionary, Vocabulary.com, https://www.vocabulary.com/dictionary/d. Accessed 11 May. 2026. Copy citation

32 meanings: 1. the fourth letter and third consonant of the modern English alphabet 2. a speech sound represented by this.... Click for more definitions.

D definition: The fourth letter of the modern English alphabet.

Definition of D noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.