| Abbreviation | Definition |
|---|---|
| CIPFO | Cyberspace and Intellectual Property Foundation Organization |
| CIRF | California International Relations Foundation |
| CISF | Conanicut Island Sailing Foundation |
| CITF | Chicago Instructional Technology Foundation |
| CKF | Central Kansas Foundation |
| CKF | Chris Klug Foundation |
| CLDF | Children's Liver Disease Foundation |
| CLEF | Chicagoland Lutheran Educational Foundation |
| CLF | Chesapeake Lighthouse Foundation |
| CLF | Childhood Leukemia Foundation |
| CLF | Chronic Love Foundation |
| CLF | Clara Lionel Foundation |
| CLF | Concussion Legacy Foundation |
| CLF | Conservation Law Foundation |
| CLFI | Child Loyalty Foundation International |
| CLMF | Calvary Life Missiomary Foundation |
| CLPF | Charles Lee Powell Foundation |
| CLRF | Camurus Lipid Research Foundation |
| CMCAF | California Mini Corps Alumni Foundation |
| CMCEF | Canadian Mechanical Contracting Education Foundation |