noun, plural D’s or Ds, d’s or ds.

  1. the fourth letter of the English alphabet, a consonant.
  2. any spoken sound represented by the letter D or d, as in dog, ladder, ladle, or pulled.
  3. something having the shape of a D.
  4. a written or printed representation of the letter D or d.
  5. a device, as a printer’s type, for reproducing the letter D or d.

  1. Electricity. debye.
  2. deep.
  3. depth.
  4. Optics. diopter.
  5. divorced.
  6. Dutch.


  1. the fourth in order or in a series.
  2. (sometimes lowercase) (in some grading systems) a grade or mark, as in school or college, indicating the quality of a student’s work as poor or barely passing.
  3. (sometimes lowercase) a classification, rating, or the like, indicating poor quality.
  4. Music.
    1. the second tone in the scale of C major, or the fourth tone in the relative minor scale, A minor.
    2. a string, key, or pipe tuned to this tone.
    3. a written or printed note representing this tone.
    4. (in the fixed system of solmization) the second tone of the scale of C major, called re.
    5. the tonality having D as the tonic note.
  5. (sometimes lowercase) the Roman numeral for 500.Compare Roman numerals.
  6. Chemistry. deuterium.
  7. Electricity.
    1. electric displacement.
    2. a battery size for 1.5 volt dry cells: diameter, 1.3 inches (3.3 cm); length, 2.4 inches (6 cm).
  8. Biochemistry. aspartic acid.
  9. a symbol for a shoe width size narrower than E and wider than C.
  10. a proportional brassiere cup size larger than C.

Symbol, Chemistry, Biochemistry.

  1. dextrorotatory; dextro- (distinguished from l-).

  1. (in prescriptions) give.

  1. British. pence.

  1. date.
  2. daughter.
  3. day.
  4. deceased.
  5. deep.
  6. degree.
  7. delete.
  8. Physics. density.
  9. depth.
  10. deputy.
  11. dialect.
  12. dialectal.
  13. diameter.
  14. died.
  15. dime.
  16. dividend.
  17. dollar; dollars.
  18. dose.
  19. drachma.

  1. contraction of had: I was glad they’d gone.
  2. contraction of did: Where’d they go?
  3. contraction of should or would:He’d like to go. I’d like to remind you of your promise.
  4. contraction of -ed: She OK’d the plan.

  1. day.
  2. December.
  3. Democrat.
  4. Democratic.
  5. Physics. density.
  6. Deus.
  7. Deuteronomy.
  8. Doctor.
  9. dose.
  10. Dutch.

  1. Symbol, Biochemistry. (of a molecule) having a configuration resembling the dextrorotatory isomer of glyceraldehyde: always printed as a small capital, roman character (distinguished from l-).


  1. de (used in French names as an elided form of de): Charles Louis d’Albert.
  2. di (used in Italian names as an elided form of di): Gabriele d’Annunzio.

  1. Pronunciation Spelling. contraction of do or did before you: How d’you like your eggs cooked? D’you go to the movies last night?

  1. (in prescriptions) daily.

noun plural d’s, D’s or Ds

  1. the fourth letter and third consonant of the modern English alphabet
  2. a speech sound represented by this letter, usually a voiced alveolar stop, as in dagger
  3. the semicircle on a billiards table having a radius of 11 1/2 inches and its straight edge in the middle of the baulk line

symbol for

  1. physics density or relative density
  2. maths a small increment in a given variable or function: used to indicate a derivative of one variable with respect to another, as in d y /d x
  3. chess See algebraic notation

symbol for

  1. music
    1. a note having a frequency of 293.66 hertz (D above middle C) or this value multiplied or divided by any power of 2; the second note of the scale of C major
    2. a key, string, or pipe producing this note
    3. the major or minor key having this note as its tonic
  2. chem deuterium
  3. maths the first derivative of a function, as in D(x ³ + x ²) = 3 x ² + 2 x
  4. physics
    1. dispersion
    2. electric displacement
  5. aeronautics drag
    1. a semiskilled or unskilled manual worker, or a trainee or apprentice to a skilled worker
    2. (as modifier)D worker See also occupation groupings
  6. (Roman numeral) 500See Roman numerals

abbreviation for

  1. Germany (international car registration)
    1. Australian informaldefenceI’m playing D in the match this afternoon
    2. Australian informaldefensive play

abbreviation for

  1. Deutsch: indicating the serial number in the catalogue (1951) of the musical compositions of Schubert made by Otto Deutsch (1883–1967)

abbreviation for

  1. (in animal pedigrees) dam
  2. daughter
  3. British currency penny or pennies
  4. diameter
  5. died
  6. dinar(s)
  7. dollar(s)
  8. drachma(s)

abbreviation for

  1. US politics Democrat(ic)
  2. government Department
  3. dinar(s)
  4. Don (a Spanish title)
  5. Duchess
  6. Duke
  7. (in the US and Canada) Doctor

contraction of

  1. would or hadI’d; you’d

fourth letter of the Roman alphabet, from Greek delta, from Phoenician and Hebrew daleth, pausal form of deleth “door,” so called from its shape. The sign for “500” in Roman numerals. 3-D for “three-dimensional” is attested from 1953.


  1. in dies (daily)


  1. Relating to the configuration of d-glyceraldehyde, a compound chosen as the basis for stereochemical nomenclature because it is the simplest carbohydrate that can form optical isomers:d-fructose.


  1. diopter
  2. dose


  1. To the right; dextro:d-tartaric acid.

  1. Abbreviation of diameter
53 queries 0.492