C1
- 1C (disambiguation)
- AEG C.I
- AGO C.I
- ATC code C01
- Advanced Configuration and Power Interface
- Advanced Level (UK)
- Albatros C.I
- Alpha Centauri Ab
- Apolipoprotein C1
- Apple silicon
- Aviatik C.I
- BMW C1
- Bavarian C I
- Bills C-1 and S-1
- C-1 Trader
- C-1 visa
- C-One
- C-class Melbourne tram
- C0 and C1 control codes
- C1 (classification)
- C1 (protocol)
- C1 (railcar)
- C1 Chemistry
- C1 Espresso
- C1 Famicom TV
- C1 Television
- C1 and P1 (neuroscience)
- C1 complex
- C1 domain
- C1 field
- C1 pylon
- C1 regulatory sequence
- C1-inhibitor
- CI (disambiguation)
- Capital One
- Cervical spinal nerve 1
- Cervical vertebra 1
- Chevrolet Corvette C1
- Chlorophyll c1
- Cierva C.1
- Cinema One
- Circumferential Road 1
- Citroën C1
- Cl (disambiguation)
- Cluster II (spacecraft)
- Common European Framework of Reference for Languages
- Counter-Strike
- Cytochrome C1
- Câble 1
- DFW C.I
- Douglas C-1
- Finnish Steam Locomotive Class C1
- Fluidigm
- Fokker C.I
- Ford C1 platform
- Friedrichshafen C.I
- GNR Class C1 (large boiler)
- GNR Class C1 (small boiler)
- Group C
- Hansa-Brandenburg C.I
- ISO 216
- Isaac Peral
- Kawasaki C-1
- LG C1
- Leapmotor C01
- List of North American broadcast station classes
- List of Olympus products
- List of Yamaha products
- Lit C-1
- London Buses route C1
- Loring R-III
- Major roads in Metro Manila
- Massachusetts State Route C1
- NER Class C1
- NGC 188
- NRS social grade
- Nimrod NRA/C1
- Otto C.I
- PRR C1
- Prime Minister of Australia
- Proanthocyanidin C1
- Prostaglandin C1
- Route C1 (Shuto Expressway)
- Rumpler C.I
- Sauber
- Schecter C-1 Hellraiser FR
- Serie C1
- Southern Cross Airport (New Jersey)
- TCSEC
- Type C1 ship
- UEFA Champions League
- Vienna Convention on Road Signs and Signals
- Vlakplaas
- Xenos (graphics chip)