D, or 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. Its name in English is dee (pronounced / ˈdiː / ⓘ), plural dees. 1, 1. The fourth letter of the modern English alphabet. 2. Any of the speech sounds represented by the letter d. 3. The fourth in a series. 4. Something shaped like the letter D. 5. D The lowest passing grade given to a student in a school or college., 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 early pictograph, possibly Egyptian, indicating the folding door of a tent., D1 / dē / (also d) • n. (pl. Ds or D's) 1. the fourth letter of the alphabet. ∎ denoting the fourth in a set of items, categories, sizes, etc. ∎ the fourth highest category of academic mark., D, or 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., The unetymological -d- is a phonetic accretion in Old French (see D). Also used in Latin to translate Aristotle's Greek grammatical term genos. The grammatical sense is attested in English from late 14c..