C3, C-3, C.3, C03, C.III or C-III may refer to:

Life and biology

* C₃ carbon fixation in plants * C3-convertase, an enzyme * Complement component 3, a protein of the innate immune system * Apolipoprotein C3, a human very low density lipoprotein * ATC code C03 ''Diuretics'', a subgroup of the Anatomical Therapeutic Chemical Classification System * Castavinol C3, a natural phenolic compound found in red wines * Cytochrome-c3 hydrogenase, an enzyme * Haplogroup C-M217, called C3 in older publications * In human anatomy, C3 may refer to: ** Cervical vertebra 3, one of the cervical vertebrae of the vertebral column ** Cervical spinal nerve 3 * Clinical Cell Culture, a medical technology company * C03, Malignant neoplasm of gum ICD-10 code * C3 Collaborating for Health, a health-promotion NGO * C3: an EEG electrode site according to the 10-20 system

Military

* C³, Command, control, and communications, a military concept * C-3 (plastic explosive), a plastic explosive related to C4 * C-3, a United States military designation for the Ford Trimotor * the designation for several German World War I and World War II armed reconnaissance aircraft ** AEG C.III ** AGO C.III, a reconnaissance biplane of World War I ** Albatros C.III ** DFW C.III, a DFW aircraft * NAG C.III, an engine powering the Gotha G.IV aircraft * C-3, a U.S. military transport version of the Martin 4-0-4 * Type C3 submarine (disambiguation), a World War II Imperial Japanese Navy cargo carrier submarine * Spanish submarine ''C-3'' * HMS ''C3'', a 1906 British C class submarine * Type C3-class ship, a type of merchant cargo ships of United States Maritime Commission "C" design * USS ''C-3'' (SS-14), a 1909 United States C class submarine * USS ''Baltimore'' (C-3), an 1888 protected cruiser of the United States Navy * Garda Crime and Security Branch (CSB), domestic security agency of Ireland's national police, also known as "C3" * C3 Howitzer, a lengthened variant of the M101 used by the Canadian Armed Forces

Technology

* C₃, characteristic energy, in astrodynamics, a measure of the rocket energy for an interplanetary mission that requires attaining an orbital velocity above escape velocity * C₃, the chemical symbol for ** Tricarbon ** Cyclopropatriene * C3.ai, an AI company founded by Thomas Siebel * Delfi-C3, a Dutch CubeSat satellite * Saturn C-3, a 1960 rocket in the Saturn C series * Chaos Communication Congress, the biggest annual hacker event in Europe * Chrysler Comprehensive Compensation System, important in the development of Extreme Programming * VIA C3, a computer processor * '' Creatures 3'', a 1999 video game * '' Crysis 3'', a 2013 video game * Cluster 3, also known as Samba, an ESA satellite

Transportation

* Aeronca C-3, an American airplane * Bavarian C III, a German steam locomotive model * Bavarian C III (Ostbahn), an 1867 German steam locomotive model * Chevrolet Corvette (C3), the third production design of the Chevrolet Corvette * Circumferential Road 3 or C-3, an arterial road of Manila, Philippines * Cierva C.3, a 1921 Spanish experimental autogyro * Citroën C3, a car * Cowin C3, a car * LB&SCR C3 class, a British LB&SCR locomotive * London Buses route C3, a Transport for London contracted bus route * C3 (railcar), a bi-level railcar built by Kawasaki Railcar for the non-electrified branches of the Long Island Rail Road * Nimrod NRA/C3, a 1983 Group C racing car never achieved * Yamaha C3, a 2007 liquid cooled 49cc four-stroke motor scooter * Two different ring expressways in Japan that are numbered C3: ** Tokyo Gaikan Expressway in Tokyo, Saitama and Chiba Prefectures ** Tōkai-Kanjō Expressway in Aichi, Gifu and Mie Prefectures

Music

* Hammond C3 organ * High C in music (c3 in European notation) * Low C in music (C3 in American notation) * '' Tha Carter III'', the title of an album by rapper Lil Wayne * C3 Presents, independent American concert promoters

Other uses

* C3 (classification), a para-cycling classification * C-3 (TV channel), a children's channel on the QUBE cable system that later became Nickelodeon * ''C³'' (light novel), a 2011 Japanese light novel series and anime by Hazuki Minase * C3, a New Zealand logistics company owned by Linx Cargo Care Group * C3, the code for permission to use specific land or premises for dwellings in town and country planning in the United Kingdom * C3, the

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in football * C3, a standard paper size defined in ISO 216 * Tippmann C-3, a pump-action paintball marker that uses propane gas * C3 Church Global, a worldwide Pentecostal denomination * C3, a class in FM radio broadcasting in North America * Argus C3, a 35mm rangefinder camera * Nokia C3 (disambiguation), various Nokia cellphones * Caldwell 3 ( NGC 4236), a barred spiral galaxy in Draco * C3 policing, a methodology being employed by police to combat gangs in Springfield, Massachusetts * Nielsen ratings that include recorded programs watched three days later * Championing Community Children, a Philippine charitable organization abbreviated as C3 * Charles Keating III (born 1955), American former swimmer and real estate executive *

Charles III Charles III (Charles Philip Arthur George; born 14 November 1948) is King of the United Kingdom and the 14 other Commonwealth realms. Charles was born at Buckingham Palace during the reign of his maternal grandfather, King George VI, and ...

(born 1948), King of the United Kingdom and 14 other Commonwealth realms since 2022. * C-III Capital Partners, an

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and commercial real estate services company *

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