| Subject | English | Welsh |
| comp., MS | compact disc read-only memory | cryno ddisg cof darllen-yn-unig (A form of storage characterized by high capacity (roughly 650 MB) and the use of laser optics instead of magnetic means for reading data) |
| comp., MS | Read mode | Modd darllen (A mode that is optimized for reading or viewing content and does not support edit functionality) |
| comp., MS | read-only | darllen-yn-unig (Capable of being retrieved (read), printed or copied but not changed (written) or saved) |
| comp., MS | read-only memory | cof darllen-yn-unig (A semiconductor circuit that contains information that cannot be modified) |
| comp., MS | read receipt | derbynneb darllen (An e-mail feature providing feedback to the sender that a message has been read by the recipient) |
| comp., MS | read/write | darllen/ysgrifennu (Able to be both read from and written to) |
| comp., MS | reading indicator | dangosydd darllen (A visual effect in the navigation pane that shows users where they are in a document) |
| comp., MS | reading pane | Cwarel Darllen (A window in an e-mail program where you can preview an item without opening it) |
| comp., MS | reading position indicator | dangosydd safle darllen (A visual effect in the navigation pane that shows users where they are in a document) |