 Close of Business | Chat and Slang |
| Chip-on-Board | Technology |
| Cobra | Organizations |
| Cargo on Board | Science |
| Collocated Operating Base | Military |
| Coordination of Benefits | Business |
| Command Operating Budget | Technology |
| Communications Office Building | Science |
| Central Obrera Boliviano | Common |
| Chief of the Boat | Military |
| Chip on Board | Military |
| Chronic Obstructive Bronchitis | Medical |
| Cisplatin, Oncovin, Bleomycin | Medical |
| City of Brass | Education |
| Clean-Out Box | Science |
| Close of Business#Name | Common |
| Co-Located Operating Base | Technology |
| Cobalamin Biosynthetic | Medical |
| Cobaltic Boride | Common |
| Cobol Source Code | Technology |