The fourth letter and third consonant in the English alphabet: the corresponding character has the same position and the same value also in the Latin, Greek, and Phenician alphabets, from which it comes to us. (See A.)As a numeral, in the Roman system, D stands for 500; when a dash or stroke is placed over it, as D, it stands for 5,000.As a symbol: In music: The second tone, or re, of the scale of C.A note which represents this tone.The key-note of the key of two sharps .On the keyboard of the organ or pianoforte, the white key or digital included in each group of two black keys.The string in a stringed instrument that is tuned to the tone D, as the third string of the violin, etc. In chem., D is the symbol of didymium.In mathematics, d is the sign of differentiation, ∂ of partial differentiation, δ of variation, D of derivation (commonly in the sense of taking the differential coefficient), ▵ of differencing, and ⾿ of the Hamiltonian operator.In the mnemonic words of logic, the sign of reduction to darii.As an abbreviation: In Eng. reckoning (d. or d.), an abbreviation of denarius, the original name for the English penny: as, £ s. d., pounds, shillings, and pence; 2s. 1d., two shillings and one penny.Before a date (d.), an abbreviation of died.In dental formulas, an abbreviation of deciduous, prefixed without a period to the letters i, c, and m: thus, di., deciduous incisor; dc., deciduous canine; dm., deciduous molar: all being teeth of the milk-dentition of a diphyodont mammal.or, more simply, taking one half of each jaw only, di. , dc. , dm. . In either case the numbers above the line are those of the upper teeth, and those below the line of the under teeth. See dental.In anatomy and ichthyology (d. or D.), an abbreviation of dorsal (vertebra or fin, respectively).In a ship's logbook (d.), an abbreviation of drizzling.A form of -ed, -ed, in certain words. See -ed, -ed.n. In music, an abbreviation of da capo.n. An abbreviation of Latin (ML.) divinitatis doctor, Doctor of Divinity.An abbreviation of the Latin defensor fidei, defender of the faith. See defender.An abbreviation of the Latin Dei gratia, by the grace of God.n. In music, an abbreviation of destra mano (which see).n. Abbreviations of Doctor of Music.An abbreviation of dead-reckoning.n. An abbreviation of dal segno.n. An abbreviation of the Latin Deo volente, God willing. See Deo volente.In music: Also, the key-note of the minor key medieval music, the final of the Dorian and Hypodorian modes.In chem.: d- before certain compounds has reference to their behavior toward polarized light, namely, to their dextrorotation, as distinguished from their inaction (i-) or levorotation (l-).In mathematics: D is also used for the number denoting the deficiency of a curve (what its number of double points lacks of the maximum).As an abbreviation: In law (D.), an abbreviation of Decree, Decret, Dictum.In medicine (d.), an abbreviation of: diopter or dioptric;dexter (right.);divide (in prescriptions).(D.) Of Democrat, Deus (God), Dominus (Lord), Dutch; (d.) of daughter, delete (cancel), density.Short for damn (often printed d—).Any mechanical device or appliance which resembles the letter D; specifically, in a harness, a loop of metal which has a straight bar joined at each end to a semicircular loop: used as a support for a strap. Also written dee. See D-trap and D-valve.n. An abbreviation of Doomsday Book.n. An abbreviation of direct current;n. of District Court;n. of District of Columbia;n. of Deputy Consul;n. of Divus Cæsar (the divine Cæsar).n. An abbreviation of Dynamical Engineer, a degree conferred at the completion of a graduate course in mechanical engineering.An abbreviation of Dean of the Faculty.An abbreviation of deadhead or deadheaded.n. An abbreviation of Deputy Lieutenant;n. of Doctor of Law, a degree equivalent to D. C. L.n. of Doctor of Literature, a degree equivalent to D. Lit.An abbreviation of Doctor of Oratoryof Doctor of Osteopathy.An abbreviation of Doctor of Pharmacy.In electricity, an abbreviation for double pole.n. An abbreviation of Doctor of Science.n. Abbreviations of Doctor of Theology.n. An abbreviation of delirium tremens.n. In electricity, of double-throw: as, a d. t. switch.
