| Acronym | Meaning |
| C | Cell (phone; science) |
| C | Copyright (usually written ©) |
| C | Transport (US military aircraft designation for transport aircraft since 1962) |
| C | Cairo (Egyptian automobile license plate) |
| C | Cedi (currency of Ghana) |
| C | Ceiling Limit (weather reports) |
| C | Charlie |
| C | Chemical |
| C | Circling (approach and landing charts) |
| C | Cliff (Stores 100 code) |
| C | Clock Mode (aviation) |
| C | Colon (currency of Costa Rica and El Salvador) |
| C | Combined (US DoD) |
| C | Commander |
| C | Comptroller |
| C | Compute(r) |
| C | Confidential |
| C | Court of Chancery (UK) |
| C | Creeping Line Pattern (US DoD) |
| C | Culver Aircrfat Corporation (US Navy aircraft) |
| C | Cum (Latin: With, often seen with a bar over the c) |
| C | Current (action code) |
| C | Federal Reserve Bank of Philadelphia, Pennsylvania (designates original point of circulation of a dollar bill) |
| C | Individual (IRB) |
| C | Prince Edward Island (Canada Post designation) |
| C | Undenominated US Stamp (20 cents, introduced 1 Nov 1981) |