D (disambiguation)

D is the fourth letter of the Latin alphabet.

D or d may also refer to:

• D River, in Oregon, US
• Detroit, US (nickname "D")

• D, the bass player for Australian band Testeagles
• "D!" or "Dee!", names of Detlef Soost, a German dancer and choreographer
• D, nickname of Indian actor Darshan (Kannada actor)
• D, nickname of Indian actor Dhanush (cf. D50 (film))

• D, a character in a series of novels titled Vampire Hunter D by Hideyuki Kikuchi
• D, a nickname given to Count Dracula in the novel Dracula written by Bram Stoker
• D, one of the characters in Another Code: Two Memories (Trace Memory)
• Count D, a character in the anime/manga series Pet Shop of Horrors
• Substance D, a fictional recreational drug in the novel and film A Scanner Darkly

• D (video game), a game released in 1995 for the PC, 3DO, PlayStation and Sega Saturn

• D (band), a Japanese rock/metal band
• D Records, a former record label in Houston, Texas, US
• "d:" or "d:?", often used to refer to the Christian rock band Delirious?
• "The D", one of the names of comedy rock band Tenacious D

• D (Deuter album), 1971
• D (Daryl Hall album), 2024
• D (Os Paralamas do Sucesso album), 1987
• D (White Denim album), 2011
• D (single album), by Big Bang, 2015
• D, followed by a number, a composition by Franz Schubert according to the Schubert Thematic Catalogue
• Substance D, a drum and bass compilation album by Dieselboy

• D (musical note)
  • D major, a scale
  • D major chord; See Chord names and symbols
  • D minor, a scale
• Steinway D-274 or D, a concert grand piano model manufactured by Steinway & Sons
• "D", a song by Little River Band from their album Playing to Win

• D, a weekly supplement to the Italian newspaper la Repubblica
• D Magazine, a magazine for the city of Dallas, Texas, US

• D (film), a 2005 Bollywood film
• Initial D, a 1995 Japanese manga and anime about mountain drifting that has spawned several arcade and console games
• D, the production code for the 1964 Doctor Who serial Marco Polo
• "D" Is for Deadbeat, the fourth novel in Sue Grafton's "Alphabet mystery" series, published in 1987
• The D logo for the Russian television channel Domashny

• Demand (D), in economics
• Dominion Resources (New York Stock Exchange ticker symbol D)
• Federal Reserve Bank of Cleveland (serial numbers of United States dollars, beginning with D)
• Penny (British pre-decimal coin) (d)

• .d, a file format used for Agilent MassHunter mass spectrometry software
• .d, a pathname component suffix for a directory; for example with the init program
• -d, a suffix of a daemon, a computer program that runs as a background process
• D - Minimal Protection, a security division in the Trusted Computer System Evaluation Criteria

• D (programming language), a C++-like programming language developed by Walter Bright
• D, a programming language designed to be used with the DTrace dynamic tracing framework

• D, Mitsubishi Electric's mobile phones in Japan
• D battery, a standard size dry cell battery in electronics
• d', sensitivity index, a statistic used in signal detection theory

• ’d, a contraction of the English words had and would
• Dingir (^D), the Sumerian sign for deity
• [d] or /d/, Voiced alveolar stop consonant in the International Phonetic Alphabet

• d, deci-, SI prefix factor 0.1

• D, a February 16 through 29 discovery in the provisional designation of a comet or asteroid
• D, for "Degenerate", a white dwarf in stellar classification
• D/, for "destroyed/disappeared" in comet nomenclature
• D region, part of the ionosphere

• D, 500 in Roman numerals
• D, Thirteen, or D in hexadecimal and other positional numeral systems with a radix of 14 or greater
• D and d, the derivative operators
• d, the symbol for the total differential operator; in a related but more general meaning, it is the exterior derivative operator in differential geometry
• d, often a variable for the diameter of a circle in geometry
• d(n), Divisor function, the number of positive divisors of an integer n
• ${\displaystyle \mathbb {D} }$ in blackboard bold, the unit disk in the complex plane, or the decimal fractions; see Number
• Cohen's d, a statistical measure of effect size.

• D, Aspartic acid, in biochemistry
  • D (or Asp), an abbreviation for the amino acid aspartate
• D, Diarrhea
• D, deuterium, an isotope of hydrogen
  • d, Deuteron, the nucleus of deuterium
• _D- prefix, a dextrorotatory compound
• ATC code D Dermatologicals, a section of the Anatomical Therapeutic Chemical Classification System
• Haplogroup D (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup
• Haplogroup D-M174, a Y-chromosomal DNA (Y-DNA) haplogroup
• Vitamin D

• D, Debye (D), a unit of electrical dipole moment
• D, Dioptre (D), a unit of measurement of the optical power of a lens or curved mirror (also in Medicine)
• D, Diffusion coefficient (D), in molecular physics
• D, Electric displacement field (D)
• D meson, mesons containing charm quarks in particle physics
• d, thickness, diameter, relative density, lattice plane spacing, and degeneracy of vibrational mode, in molecular spectroscopy
• D band (disambiguation)

• D(E), a function of energy
• Debye–Waller factor (D)
• Diode (D), an electronic component
• Wavenumber [D(k)], a symbol for the density of states

• Day (d), in metrology
• December (D), in calendars
• Dominical letter D, for a common year starting on Thursday

• D (Los Angeles Railway), a line operated by the Los Angeles Railway, US
• D (New York City Subway service), US
• D Line (Los Angeles Metro), US
• Drive, or D, the forward cruising gears in an automatic transmission
• Tesla Model D, a concept all-wheel drive electric sedan
• Line D of the Buenos Aires Subte
• , the official West Japan Railway Company service symbol for the JR West Nara Line.
• Media–Sharon Hill Line, a SEPTA Metro service, labeled D
• The international vehicle registration code for Germany (Deutschland)

• D, a normal modal logic
• D (grade), a below average grade in education
• D, a brassiere cup size
• d, the number of sides of dice in role-playing games
• d, the common US measurement of the penny size (an approximation of length), of a nail
• D-Company, a criminal group
• Daughter (d)
• Defense (sports) (D)
• Democrat (D), a member of the US Democratic Party
• Denarius, a Roman coin
• Died (d.)
• Dominant person (D/), in dominance and submission
• Delta, the military time zone code for UTC+04:00

• D♯ (disambiguation)
• D. (disambiguation)
• D- All Things Digital, an annual technology conference
• Dee (disambiguation)
• Filetab-D, a port of the Filetab language based on decision tables