D2
D2, D02, D.II, D II or D-2 may refer to:
Places
- Dublin 2, a Dublin, Ireland postcode
 - Mount Dulang-dulang, the second highest mountain of the Philippines
 - D2, a line of Moscow Central Diameters
 - D2 Place One and Two, at Cheung Yue Street and Cheung Shun Street, in Cheung Sha Wan, MTR Lai Chi Kok Station Exit D1 and D2.
 
Highways
- D2 motorway (Czech Republic)
 - D2 road (Croatia), a state route in Croatia
 - D2 motorway (Slovakia)
 
Arts & entertainment
- D-2 (mixtape), a 2020 album by South Korean rapper Agust D
 - D2: The Mighty Ducks, the second film in The Mighty Ducks trilogy
 - R2-D2, a robotic Star Wars character
 - "D²", a 2002 episode of Dexter's Laboratory
 - D2 (video game), a 1999 game for the Sega Dreamcast
 - D2, an abbreviation of the video game Diablo II or Destiny 2
 - D2, a sub-group of the Japanese male acting troupe D-Boys
 - Dhoom 2, a 2006 Indian Hindi-language action film by Sanjay Gadhvi, second part of the Dhoom film series
 
Business
- D2 (hotel chain), owned by Dusit Thani Group
 - D2 Mannesmann, the former name of Vodafone's German division, which resulted from the acquisition of the German company Mannesmann AG
 - D2 (magazine), published by Dagens Næringsliv
 - D2, the IATA code for Damania Airways
 
Biology or medicine
- ATC code D02 Emollients and protectives, a subgroup of the Anatomical Therapeutic Chemical Classification System
 - Dopamine receptor D2, a protein
 - Levuglandin D2
 - Prostaglandin D2 receptor, a G-protein coupled receptor
 - Resolvin D2
 - Cyclin D2 (CCND2)
 - Vitamin D2, or ergocalciferol
 - D02, the ICD-10 code for carcinoma in situ of middle ear and respiratory system
 - DIO2, Type II iodothyronine deiodinase, an enzyme involved in the thyroid system
 
Vehicles
Aircraft
- Albatros D.II, a 1916 German fighter aircraft
 - Aviatik (Berg) D.II, a 1917 -Hungarian fighter prototype
 - STS-55 or D2, the second German-sponsored Spacelab mission
 - Daimler D.II, a Daimler aircraft
 - Delta D2, an Australian diesel-powered helicopter design
 - Dunne D.2, a British Dunne aircraft
 - Euler D.II, a 1917 German single-seat fighter
 - Fokker D.II, a WWI German fighter biplane
 - Halberstadt D.II, a 1916 German biplane fighter aircraft
 - Hughes D-2, a 1943 mysterious American fighter and bomber project
 - LFG Roland D.II, a 1917 German single-seat fighter
 - Phönix D.II, a variant of the Hungarian First World War biplane fighter D.I
 - Schütte-Lanz D.II, a 1915 variant of the German Schütte-Lanz D.I aircraft
 
Aircraft engines
- Alfa Romeo D2, a 1931 Italian nine-cylinder radial engine for aircraft use
 - Mercedes D.II, a WWI 6-cylinder, liquid-cooled inline aircraft engine
 
Locomotives
- Bavarian D II, an 1898 German goods train tank locomotive model
 - Bavarian D II (Ostbahn), an 1866 German goods train tender locomotive model
 - Bavarian D II (old), an 1873 small tank locomotive
 - GS&WR Class D2, a Great Southern and Western Railway Irish steam locomotive
 - LB&SCR D2 class, a British locomotive class
 - GNR Class D2, a class of British steam locomotives
 - PRR D2, an 1868 American steam locomotive model
 
Ships
- HMS Attacker (D02), a 1941 American-built escort aircraft carrier
 - HMS Devonshire (D02), a 1962 County-class destroyer
 - HMS Inglefield (D02), a 1936 I-class destroyer and flotilla leader of the British Royal Navy
 - USS D-2 (SS-18), a 1909 American submarine
 
Other vehicles
Electronics
- Cowon D2, a 2007 portable media player with touch screen interface
 - Datasaab D2, a Swedish concept computer completed in 1960
 - d2, a brand of computer peripherals manufactured by the French firm électronique d2, now trading as LaCie
 - D2 kit, a microprocessor development kit MEK6800D2
 - D-2 (video), a professional digital video format
 - DOCSIS 2, a cable modem standard
 
Other uses
- D2, the Codex Claromontanus, a 6th-century Greek-Latin uncial manuscript of the New Testament
 - D2, a dihedral group in group theory
 - D2, deuterium, an isotope of hydrogen
 - D2, an almond-shaped cloud on Neptune
 - D2, the code for permission to use specific land or premises for leisure (cinemas, swimming baths, gymnasiums) in town and country planning in the United Kingdom
 - D2, the Double Dragon hacking group
 - Division II (disambiguation), in sports leagues, etc.
 - Marcelo D2 (born 1967), Brazilian rapper
 - D2, an abbreviation for DOCSIS 2.0, an international telecommunications standard
 - D2 steel, a type of D-Grade tool steel with good wear resistance commonly found in shears and high-end knives
 - D2, gaming notation for a 2-sided die, such as a coin
 - D2, a standard paper size between B2 and A1
 - D2 Subway, a planned Dallas, Texas light rail tunnel