| Subject | Estonian | English |
| comp., MS | Office Open XML-vormingud | Office Open XML formats (An international open standard for word-processing documents, presentations, and spreadsheets that can be freely implemented across multiple applications and platforms) |
| comp., MS | Open Shortest Path First | open shortest path first (A routing protocol for Internet Protocol (IP) networks. OSPF allows a router to calculate the shortest path to each node for sending messages. The router sends information on the nodes it is linked to, called link-state advertisements, to other routers on the network to accumulate link-state information to make its calculations) |
| comp., MS | Open Systems Interconnection | Open Systems Interconnection model (A networking model introduced by the International Organization for Standardization (ISO) to promote multi-vendor interoperability. OSI is a seven-layered conceptual model consisting of the application, presentation, session, transport, network, data-link, and physical layers) |
| comp., MS | Open XML-vormingud | Open XML formats (An international open standard for word-processing documents, presentations, and spreadsheets that can be freely implemented across multiple applications and platforms) |