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

Life and biology

* C3 carbon fixation, 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, Oral cancer, 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 (EEG), 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, Spanish submarine ''C-3'' * HMS C3, 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), USS ''C-3'' (SS-14), a 1909 United States C class submarine * USS Baltimore (C-3), 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 howitzer, 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 * C3 linearization, a computer science algorithm for resolving the order of method resolution in multiple inheritance conditions * 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

* 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 * 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 where 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 * C3 (light novel), ''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, 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 UEFA Europa League 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 List of North American broadcast station classes#FM, 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 (born 1948), King of the United Kingdom and 14 other Commonwealth realms since 2022. * C-III Capital Partners, an asset management and commercial real estate services company

Life and biology

Military

Technology

Transportation

Music

Other uses

See also