| Abbreviation | Definition |
|---|---|
| RE | Requirements engineering |
| REA | Ripple Effect Analysis |
| REC | Regular Expression Compiler |
| RECADE | Receive Capture Deliver |
| RECS | Realistic Enviroment and Climate Simulator |
| REFS | Resilient File System |
| REN | Rename |
| REPO | Repository |
| REPOS | Repository of Erlang Projects Organization Software |
| REQ | Requires |
| RERS | Remote Emergency Response Software |
| REST | Relative Expression Software Tool |
| REV | Review |
| REV | Revision |
| REVIT | Revise Instantly |
| REXML | Ruby Electric XML |
| REXX | REstructured eXtended eXecutor |
| RFA | Risk Factor Analysis |
| RFE | Request For Enhancement |
| RFE | Request For Feature Enhancement |