C3
- 10-20 system (EEG)
- 195 (number)
- 3C (disambiguation)
- AEG C.III
- AGO C.III
- ATC code C03
- Aeronca C-3
- Albatros C.III
- Apolipoprotein C3
- Argus C3
- Bavarian C III
- Bavarian C III (Ostbahn)
- C (programming language)
- C-3 (TV channel)
- C-3 (plastic explosive)
- C3 (classification)
- C3 (light novel)
- C3 (railcar)
- C3 Church Global
- C3 Collaborating for Health
- C3 Presents
- C3 Racing
- C3 carbon fixation
- C3 policing
- C3-convertase
- C3.ai
- CCC (disambiguation)
- Castavinol C3
- Cervical spinal nerve 3
- Cervical vertebra 3
- Championing Community Children
- Chaos Communication Congress
- Charles III
- Charles Keating III
- Chevrolet Corvette (C3)
- Chrysler Comprehensive Compensation System
- Cierva C.3
- Circumferential Road 3
- Citroën C3
- Clinical Cell Culture
- Cluster 3
- Command, control, and communications
- Complement component 3
- Cowin C3
- Creatures 3
- Crysis 3
- Cyclopropatriene
- Cytochrome-c3 hydrogenase
- DFW C.III
- Delfi-C3
- Ford Trimotor
- Garda Crime and Security Branch
- HMS C3
- Hammond C3 organ
- Haplogroup C-M217
- Hexadecimal
- High C
- ISO 216
- Linx Cargo Care Group
- List of North American broadcast station classes
- London Buses route C3
- Low C
- M101 howitzer
- Martin 4-0-4
- NAG C.III
- NGC 4236
- Nielsen ratings
- Nimrod NRA/C3
- Nokia C3 (disambiguation)
- Oral cancer
- Saturn C-3
- Spanish submarine C-3
- Tha Carter III
- Thomas Siebel
- Tippmann C-3
- Tokyo Gaikan Expressway
- Tricarbon
- Type C3 submarine (disambiguation)
- Type C3-class ship
- Tōkai-Kanjō Expressway
- UEFA Europa League
- USS Baltimore (C-3)
- USS C-3 (SS-14)
- VIA C3
- Yamaha C3