The meaning of the Acronym FOS is...

FOS is

• Faint Object Spectrograph (on HST)
• Flight Operations Support

More Meanings For FOS:

• Forensic and Osteoarchaeological Services
• Fructo-OligoSaccharide
• Free Online Scholarship
• Furniture Online Shop
• Friends Of Scouting
• Forward Observer System
• Full Of Shit
• Faint Object Spectrograph (on HST)
• Flight Operations Support
• Federación Obrera Socialista
• Freak Out Squad
• Full of stool (constipated)
• Full Of Shit
• Fantastically Oaky Stuff
• Finkel Osteogenic Sarcoma

FOS is also in:

• Adults
• Botany
• Chat
• Chemistry
• Firms
• Funnies
• Military
• NASA
• Physiology
• Scouting
• Spanish
• Unfiled
• Universities