Wikipedia
OSR
OSR may refer to:
- Leoš Janáček Airport Ostrava's IATA code
- Oil-Steam Ratio, the ratio of oil produced to steam injected, in the extraction of petroleum
- Oilseed rape, (Brassica napus), also known as rapeseed
- Old School Revival, also known as Old School Renaissance, a movement within Dungeons and Dragons and Tabletop role-playing games
- On-Stack-Replacement, in Java HotSpot virtual machines, the conversion of a running function’s interpreter frame into a just-in-time (JIT) frame in the middle of that method
- Ontario Southland Railway, a short line railway operating in Southern Ontario, Canada
- Ontario Student Record
- Open-source religion, belief systems created through open-source methodologies
- Open Space Ratio, the ratio of unbuilt to built terrain, in urban planning
- Operation Summer Rains, also known as the 2006 Israel–Gaza conflict
- Operational sex ratio, ratio of reproductively available males to females
- Operational System Review, in air traffic control
- Optical solar reflector, a radiator material for space craft
- Outgoing Shortwave Radiation, in atmospheric physics
- Oversampling Ratio, in Sampling (signal processing)
- Owasippe Scout Reservation, a Boy Scout camp in Twin Lake, Michigan
- Texas State Highway OSR, a section of the Old San Antonio Road