| Capt | Captain |
| CB | Companion of the Order of the Bath |
| Cdr | Commander |
| Cdre | Commodore |
| centl | central |
| Ch | Chief |
| Ch Ch | Christ Church |
| Chllr | Chancellor |
| Chm | Chairman |
| CIA | Central Intelligence Agency |
| CIE | Companion of the Order of the Indian Empire |
| CMG | Companion of the Order of St Michael and St George |
| cmmdg | commanding |
| Cmmn | Commission |
| Cmmr | Commissioner |
| Cncl | Council |
| Co | County or Company |
| Col | Colonel |
| Coll | College |
| Conf | Conference |
| Confed | Confederation |
| Conventn | Convention |
| Corp | Corporation |
| CPA | Certified Public Accountant |
| Cpl | Corporal |
| Ctee | Committee |
| CVO | Commander of the Royal Victorian Order |