D
D1 / dē/ (also d) • n. (pl. Dsor 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.2. (D) a shape like that of a capital D: [in comb.] the D-shaped handle. ∎ a loop or ring of this shape.3. (usu. D) Mus. the second note of the diatonic scale of C major. ∎ a key based on a scale with D as its keynote.4. the Roman numeral for 500.D2 • abbr. ∎ Democrat or Democratic. ∎ depth (in the sense of the dimension of an object from front to back). ∎ Chem. dextrorotatory: D-glucose. ∎ (with a numeral) dimension(s) or dimensional: a 3-D model. ∎ (in tables of sports results) drawn. ∎ (on an automatic gearshift) drive. ∎ (in personal ads) divorced.• symb. ∎ Physics electric flux density. ∎ Chem. deuterium.
