| Abbreviation | Definition |
|---|---|
| CHO | Carbohydrate |
| CHO | Carbon Hydrogen and Oxygen (Carbohydrate) |
| CHP | Chemical Hygiene Plan |
| CHW | Clostridial Hydrophobic with a conserved W |
| CHWP | Chemical Hygiene Work Plan |
| CI | Chemical Impurities |
| CI | Chemistry & Industry Magazine (Industrial chemistry magazine published in London) |
| CI | Composite Index |
| CIAC | Changchun Institute of Applied Chemistry |
| CICAD | Concise International Chemical Assessment Documents |
| CICC | Chemical Industry Council Of California |
| CICI | Chemical Industry Council of Illinois |
| CID | Collision-Induced Dissociation |
| CIE | Carbon Isotope Excursion |
| CII | Chemical Input Instruction |
| CIK | Cytokine Induced Killer |
| CIMS | Chemical Ionisation Mass Spectrometer |
| CIN | Chemical Industry Notes |
| CIP | Cesium Intermediate Product |
| CIPL | Chemical Industrial Pharmaceutical Laboratories |