| Acronym | Definition |
|---|
| RADIUS | Remote Authentication Dial in User Service |
| RADIUS | Research and Development in the United States |
| RADIUS | Routine Antenatal Diagnostic Imaging with Ultrasound Study (obstetrics and gynecology) |
| RADIUS | Remote Access Dial-In User Server |
| RADIUS | Research And Development for Image Understanding Systems |
| RADIUS | Rheumatoid Arthritis DMARD (Disease Modifying Antirheumatic Drug) Intervention and Utilization Study |
| RADIUS | Remote Authentication Dial-In User Server/Service (networking protocol) |
| RADIUS | Remote Authentication Dial in User System (computer networks) |
| RADIUS | Remote Aims Data Input User System (New Jersey) |
| RADIUS | Research Archive on Disability in the United States (database) |