C1
| Acronym | Definition |
|---|---|
| C1 | Methane |
| C1 | Atlas (first cervical vertebra; common name) |
| C1 | Canoe (one person) |
| C1 | Capital One |
| C1 | Composition 1 (plastic explosive) |
| C1 | Capability 1 |
| C1 | Schedule I Controlled Substance (USA) |
| C1 | Cyclopentolate 1% Eyedrops |
| C1 | CPU State 1 (non-executing computing mode) |