English abbreviations from obs to oc
- OBS (Omnibearing selector)
- OBSAI (Open Base Station Architecture Initiative)
- OBSB (Oahu Base Support Battalion)
- OBSS (Off Board Sensor Systems)
- OBST (Obstacle)
- OBSTINTEL (Obstacle Intelligence)
- OBT (Oakland/coliseum Stat Airport)
- OBU (Kobuk Airport)
- OBX (Outer Banks (North Carolina))
- OBY (Ittoqqortoormiit Heliport)
- oc (Occitan language (ISO 639-1 code))
- O.C. (Ordo C(h)aritatis (Fathers of the Order of Charity))