Encyclopedias, Almanacs, Transcripts, and Maps
- Radio City
- radio compass
- Radio Frequencies ( (table))
- radio frequency
- radio range
- radio-frequency identification
- radioactive isotope
- radiochemistry
- radiological weapon
- Radishchev, Aleksandr Nikolayevich
- Raditch, Stefan
- radium emanation
- Rafa
- Raffet, Denis Auguste Marie
- Ragaz, Bad
- ragged robin
- Raguel
- Ragusa (city, Croatia)
- Ragusa (city, Italy)
- ragwort