| FOS | Fabry Outcome Survey 
| Others |
| FOS | Factor Of Safety
| Others |
| FOS | Factored Operating System
| Others |
| FOS | Factory Outlet Store
| Others |
| FOS | Faculty Of Science
| Others |
| FOS | Failover Services
| Others |
| FOS | Faint Object Spectrograph
| Others |
| FOS | Family Of Service
| Others |
| FoS | Family of Services
| Others |
| FoS | Family of Systems
| Others |
| FOS | Fantastically Oaky Stuff
| Others |
| FOS | Fear Of Socializing
| Others |
| FOS | Feat Of Strength
| Others |
| FOS | Fedora Operating System
| Others |
| FOS | Ferry Operators Service
| Others |
| FOS | Festival of Speed
| Others |
| FOS | Fiber optic Sensor
| Others |
| FOS | Fibre Optic Service
| Others |
| FOS | FIDUCIAL Office Solutions
| Others |
| FOS | Field Of Study
| Others |
| FOS | File Organization System
| Others |
| FOS | File Output Stream
| Others |
| FOS | Filozoikos Oikologikos Syllogos
| Others |
| FOS | Financial Ombudsman Service
| Others |
| FOS | Financial Origination System
| Others |
| FOS | Finger Of Suspicion
| Others |
| FOS | Finkel Osteogenic Sarcoma
| Others |
| FOS | First Of the Season
| Others |
| FOS | Fleet Online Solutions
| Others |
| FOS | Flexible Open And Social
| Others |
| FOS | Flight Operation Security
| Others |
| FOS | Flight Operations Segment
| Others |
| FOS | Flight Operations Support
| Others |
| FOS | Flight Operations System
| Others |
| FOS | Florida Ornithological Society
| Others |
| FOS | Follow On Support
| Others |
| FOS | Ford Of Spain
| Others |
| FOS | Ford Of Sweden
| Others |
| FOS | Forensic and Osteoarchaeological Services
| Others |
| FOS | Forester S
| Others |
| FOS | Forrest, Western Australia, Australia
| Others |
| FOS | Fortress Of Solitude
| Others |
| FOS | Forward Observer System
| Others |
| FOS | Forward Operating Site
| Others |
| FOS | Found On Shelf
| Others |
| FOS | Foundations of Success
| Others |
| FOS | Foundry Of Space
| Others |
| FOS | Four Owners Share
| Others |
| FOS | Freak Out Squad
| Others |
| FOS | Free Online Scholarship
| Others |
| FOS | Freedom Of Speech
| Others |
| FOS | Friend Of Sauce
| Others |
| FOS | Friend of the Sea
| Others |
| FOS | Friends Of Scouting
| Others |
| FOS | Friends of Severndale
| Others |
| FOS | Friends Of Stern
| Others |
| FOS | Friends Of Symfony
| Others |
| FOS | Friends of the Sheriff
| Others |
| FOS | Front Of Store
| Others |
| FOS | Fructo-OligoSaccharide
| Others |
| FOS | Full Of S***
| Others |
| FOS | Full Of Sh*t
| Others |
| FOS | Full Of Stool (constipated)
| Others |
| FOS | Full Operational Status
| Others |
| FOS | Full Order Scan
| Others |
| FOS | Functional Operational Spcification
| Others |
| FOS | Fundamental Operating System
| Others |
| FOS | Furniture Online Shop
| Others |
| FOS | Open Scouting
| Others |
| FOS | The Fisheries Operation System
| Others |