| Open city | Città aperta |
| Open cluster | Ammasso aperto |
| Open content | Open content |
| Open Database Connectivity | ODBC |
| Open Directory Project | Open Directory Project |
| Open dump | Mondezzaio |
| open eyed | con gli occhi spalancati |
| Open field system | Campi aperti |
| open fire | fuoco nel caminetto |
| Open format | Formato aperto |
| open freight car | pianale |
| Open Gaming License | Open Gaming License |
| open handed | liberale |
| Open hearth furnace | Forno Martin-Siemens |
| open house | giorno di ricevimento |
| Open into | Sboccare in |
| open lawn | prato coltivato |
| Open mapping theorem | Teorema della funzione aperta |
| Open Network Computing Remote Procedure Call | ONC RPC |
| Open on to | Affacciarsi su |
| open railroad freight car | pianale |
| Open reading frame | Open reading frame |
| open sea | largo |
| open sea fishing | pesca d'altura |
| Open set | Insieme aperto |
| Open Sound System | Open Sound System |
| Open source | Opensource |
| Open Source Definition | Open Source Definition |
| Open Source Development Labs | OSDL |
| Open Source Intelligence | OSINT |
| Open source movement | Opensource |
| Open source religion | Yoismo |
| Open source software | Opensource |
| open space | spazio aperto |
| Open Space Technology | Open Space Technology |
| Open spectrum | Open Spectrum |
| Open star cluste | Ammasso aperto |
| Open star cluster | Ammasso aperto |
| Open star clusters | Ammassi aperti |
| Open straight out into | Affacciarsi su |
| open the eyes | disingannare |
| Open universe | Universo aperto |
| Open Your Eyes | Open Your Eyes |
| Open Your Heart | Open Your Heart |
| open-air | all'aperto |
| open-air dance-hall | balera |
| open-ended | senza limiti precisi |
| open-eyed | con gli occhi spalancati |
