| Acronym | Definition |
|---|
| FSO➣Free Space Optics |
| FSO➣Free Space Optical |
| FSO➣File System Object (Microsoft) |
| FSO➣Faculté des Sciences Oujda (French: Oujda Science Faculty; Oujda, Morocco) |
| FSO➣Facilities Security Officer |
| FSO➣Fire Safety Order (regulation) |
| FSO➣Foreign Service Officer |
| FSO➣Fabryka Samochodow Osobowych |
| FSO➣File System Object |
| FSO➣Field Service Organization |
| FSO➣Field Selector Outside |
| FSO➣Floating Storage and Offloading (supertankers usually used for oil shipping) |
| FSO➣Federal Statistical Office (Germany) |
| FSO➣Full Scale Output |
| FSO➣Fire Support Officer |
| FSO➣Freesmartphone |
| FSO➣Financial Service Organization |
| FSO➣Flag Service Organization (Scientology) |
| FSO➣Fabryka Samochodow Osobowych (Poland passenger automobile factory) |
| FSO➣Fund for Special Operations |
| FSO➣Family Support Organization |
| FSO➣Floating Storage Offloading |
| FSO➣Flotilla Staff Officer |
| FSO➣File Scripting Object (computing) |
| FSO➣Field Security Operations |
| FSO➣Financial Services Officer |
| FSO➣Full Spectrum Operations |
| FSO➣Flight Safety Officer |
| FSO➣Food Service Officer |
| FSO➣Field Security Officer (United Nations) |
| FSO➣Flagstaff Symphony Orchestra (Flagstaff, Arizona) |
| FSO➣Fox Sports Ohio |
| FSO➣Full Sail University Online (Winter Park, FL) |
| FSO➣Field Security Office |
| FSO➣Flint Symphony Orchestra (Flint, Michigan) |
| FSO➣First Star Online (game) |
| FSO➣Food Stamp Outreach (various organizations) |
| FSO➣Funeral Service Operative (undertaker) |
| FSO➣Forum Support Organisation |
| FSO➣Former Significant Other |
| FSO➣Financial Sanctions Officer |
| FSO➣Freinage du Sud-Ouest (French: Braking Southwest) |
| FSO➣For Services Of |
| FSO➣Friday Shout Out |
| FSO➣Financial Services of Ontario |
| FSO➣Field Service Officer |
| FSO➣Fender Shaped Object (musical instruments) |
| FSO➣Facilities Service Office (USPS) |
| FSO➣Federalnaya Sluzhba Okhrany (Russian: Federal Security Organization; successor of GUO and SBP) |
| FSO➣Field Service Office |
| FSO➣Fail-Safe Open |
| FSO➣Field Sales Office |
| FSO➣Family Service Ontario |
| FSO➣Fleet Support Operations |
| FSO➣Fill Station Operator |
| FSO➣Flight Surgeon's Office |
| FSO➣Full Service Office |
| FSO➣Fleet Support Officer |
| FSO➣Fuel Service Option (automobile rental) |
| FSO➣Firewall Security Officer |
| FSO➣Flight System Operations (US NASA) |
| FSO➣Fuel Supply Office |
| FSO➣Fédération Suisse des Osthéopathes (French: Swiss Federation of Osteopaths) |
| FSO➣Facilities and Services for Older Persons |
| FSO➣Facility Support Operator |
| FSO➣Facility Security Officer/Supervisor |
| FSO➣Field Service Orders (accounting software) |
| FSO➣Freshman Scholarship Options |
| FSO➣Familles Sang et Or (French: Blood and Gold Families; Belgium) |
| FSO➣Factory Shipping Order |
| FSO➣For Spares Order |
| FSO➣Form, Space, and Order |
| FSO➣Free Standing Option (new vehicle option that is not sold as part of a package) |
| FSO➣Fixed Site of Operation |
| FSO➣Force Structure Option |