| O-Kuni-Nushi | Ōkuninushi |
| O-Zone | O-Zone |
| o.s.a. | R.S.V.P. |
| oacceptabel | unacceptable |
| oacceptabelt | unacceptable |
| oackompanjerad | unaccompanied |
| oadlig person | commoner |
| Oahu | Oahu |
| Oak Island | Oak Island |
| Oakland | Oakland |
| Oakland Athletics | Oakland Athletics |
| Oakland International Airport | Oakland International Airport |
| Oakland Raiders | Oakland Raiders |
| oaktat | despite |
| oaktsam | careless |
| oaktsamhet | carelessness |
| oanad | unhoped-for |
| oangenäm | repugnant |
| oangenäm följd | repercussion |
| oangriplig | unimpeachable |
| oanmäld | unannounced |
| oannonserad | unheralded |
| oansenlig | homely |
| oanskaffbar | unobtainable |
| oanständig | nasty |
