| Resident Students Association | Academic & Science |
| Research Society on Alcoholism | Academic & Science |
| Regional Studies Association | Academic & Science |
| Rhetoric Society of America | Academic & Science |
| Royal Society for the Encouragement of Arts, Manufactures and Commerce | Academic & Science |
| Royal Scottish Academy | Academic & Science |
| Rising Star Academy | Academic & Science |
| Research Set Aside | Academic & Science |
| Research Scholar Award | Academic & Science |
| Santa Rosa | Airport Code |
| Reactor Studios Amsterdam | Business |
| Rochester Software Associates | Business |
| Restoration Sciences Academy | Business |
| Royal & Sun Alliance Insurance Company | Business |
| REALTOR Senior Advisor | Business |
| Registered Service Agency | Business |
| Retirement Savings Account | Business |
| Royal and Sun Alliance | Business |
| RSA Insurance Group, P.L.C. Ordinary shares | Business |
| Radical Scavenging Activity | Chemistry |
| Royal Society of Arts | Community |
| Recycled & Secondary Aggregate | Community |
| Responsible Serving of Alcohol | Community |
| Rancho San Antonio | Community |
| Restoring Sustainable Abstraction | Community |
| Resident Student Association | Community |
| Rent Stabilization Association | Community |
| Resident Service Associates | Community |
| Riverside Sheriffs Association | Community |
| Public Key Cryptosystem invented by Rivest, Shamir and Adleman | Computer and Networking |
| Rural Service Area | Computer and Networking |
| Remote Supervisor Adapter | Computing |
| Reference System Architecture | Computing |
| Rivest Shamir Adleman Encryption | Computing |
| Rural Serving Area | Computing |
| Remote Sensing Architecture | Computing |
| Reset System Activity | Computing |
| Repair Service Attendant | Computing |
| Remote Session Access | Computing |
| Resistance Sink To Air | Electronics |
| Rock Solid Algorithm | General |
| Rivest Shamir and Adleman | General |
| Responsible Service of Alcohol | General |
| Rivest Shamir Adelman | General |
| Road Safety Audits | General |
| Rivest Shamir and | General |
| Rivest Shamir and Adelman | General |
| Rehabilitative Services Administration | General |
| Revised Shapley Ames | General |
| SecurID Access | General |
| Rear Seat Audio | General |
| Roadside Assistance Service | General |
| Right Side Airbags | General |
| Road Safety Act | General |
| Renault South Africa | General |
| Renault Societe Anonyme | General |
| Rear Shock Absorber | General |
| Road Safety Audit | General |
| Road Safety Adviser | General |
| Road Safety Authority | General |
| Road Safety Association | General |
| Rear Suspension Assembly | General |
| Road Stability Advantage | General |
| Rally South Africa | General |
| Road Safety Advocates | General |
| Road Service Area | General |
| Road Sign Assist | General |
| Renault Sport Academy | General |
| Road Safety Awards | General |
| Road Side Assistance | General |
| Rear Seat Alert | General |
| Red Sprites Army | General |
| Red Sonic Awards | General |
| Renaissance Society of America | General |
| Really Sweet Activities | General |
| Retirement Systems of Alabama | General |
| Real Sex Addicted | General |
| Rivest Shamir Algorithm | General |
| Rate Stabilization Account | General |
| Reading Sufficiency Act | General |
| Registrar Staging Assistant | General |
| Registration Services Agreement | General |
| Rear Seat Accessory | General |
| Rehabilitation Services Administration | Governmental |
| Runway Safety Area | Governmental |
| Revised Statutes Annotated | Governmental |
| Ritual Sexual Abuse | Governmental |
| Revised Statute Annotations | Governmental |
| Radiation Safety Academy | Governmental |
| Retirement System of Alabama | Governmental |
| Registered Sex Offender | Governmental |
| Random Sexual Act | Governmental |
| Redstone Arsenal | Governmental |
| Republic of South Africa | Governmental |
| Reduced Speed Ahead | Governmental |
| RISAMA | Indian Railway Station |
| Rivest Shamir Adleman | Information Technology |
| Regional Support Administrator | Jobs |
| Regional Specialty Adviser | Jobs |
| Recurrent Spontaneous Abortion | Medical |
| Rehabilitation Services | Medical |
| Respiratory Sinus Arrhythmia | Medical |
| Rapid Slide Agglutination | Medical |
| Reactive Secondary Amyloidosis | Medical |
| Regular Spiking Activity | Medical |
| Right Subclavian Artery | Medical |
| Returned Services Association | Military and Defence |
| Retrograde Storage Area | Military and Defence |
| Regimental Support Area | Military and Defence |
| Santa Rosa, LP, Argentina | Regional |
| Revised Statutes of Alberta | Regional |
| Republic South Africa | Regional |
| Republiek van Suid-Afrika (Republic of South Africa) | Regional |
| Rail Sling Attachment | Regional |
| Rational Software Architect | Softwares |
| Russian Space Agency | Space Science |
| Reference Satellite A | Space Science |
| Roller Skating Association | Sports |
| Raleigh Swimming Association | Sports |
| Range Standardization and Automation | Sports |
| Roller Skating Association International | Sports |
| Riding School Assistant | Sports |
| Run Straight Ahead | Sports |
| Santa Rosa Airport | Transport & Travel |
