| Acronym | Definition |
|---|
| FCSO | Franklin County Sheriff's Office (various locations) |
| FCSO | First Coast Service Options, Inc. (Medicare administrator) |
| FCSO | Forsyth County Sheriff's Office (Winston-Salem, NC) |
| FCSO | Fight Club Septème-Oytier (French martial arts club) |
| FCSO | Froid Climatisation Sud Ouest (French: Southwest Cold Air) |
| FCSO | Fort Collins Symphony Orchestra |
| FCSO | Franklin County Senior Options (Ohio) |
| FCSO | Football Club Saint Omer (French football club) |
| FCSO | Fédération Canadienne des Sociétés Orchidophiles (French: Canadian Orchid Congress) |
| FCSO | Forum of Civil Society Organisations |