| Word | Description |
| Radio frequency identification tags (RFID) | Come in many shapes and sizes, such as tags and cards. They are able to store more data than a conventional magnetic strip card with the advantage that the stored information can be easily and automatically updated. |
| RAM (random access memory) | The amount of memory in your computer, which is available to programs. |
| RDBMS (relational database management system) | A database management for a relational database. |
| Real-time | An operating system that responds to an external event within a short and predictable time frame. |
| Relational database | A database system that is organised and accessed according to the relationships between data items. |
| Repository | A facility for storing descriptions and behaviours of objects within an organisation, and is a single point of access for definitions on all system resources. |
| Router | Hardware that routes data within a network. They can also be used to allow only authorised machines to transmit data into a local network. |