| Acronym | Definition |
|---|
| Ru | Russian (linguistics) |
| Ru | Russia (top level domain) |
| Ru | Are You? |
| Ru | Rockefeller University |
| Ru | Rack Unit |
| Ru | Rhodes University (Grahamstown, South Africa) |
| Ru | Radford University |
| Ru | Rugby Union |
| Ru | Rutgers University |
| Ru | Reino Unido (Spanish: United Kingdom) |
| Ru | Royaume Uni (French: United Kingdom) |
| Ru | Real User (web page visitors) |
| Ru | Ruthenium |
| Ru | Rice University |
| Ru | Radboud University Nijmegen (Netherlands) |
| Ru | Root User (Linux) |
| Ru | Resource Unit (computing) |
| Ru | Rowan University (Glassboro, NJ) |
| Ru | Rutherfordium |
| Ru | Rider University (New Jersey) |
| Ru | Ryerson University (Toronto, Ontario, Canada) |
| Ru | Rød Ungdom (youth section of Rød Valgallianse) |
| Ru | Restaurant Universitaire |
| Ru | Renouvellement Urbain (French: Urban Renewal) |
| Ru | Rig Up (oil driliing) |
| Ru | Rescue Unit |
| Ru | Remote Unit |
| Ru | Reykjavik University (Iceland) |
| Ru | Request/Response Unit |
| Ru | Replaceable Unit |
| Ru | Radio Userland (software) |
| Ru | Refrigeration Unit |
| Ru | Radio Unit |
| Ru | Receive Unit |
| Ru | Residential Unit |
| Ru | Release Unit |
| Ru | Radioulnar (joint) |
| Ru | Ridna Ukraina |
| Ru | Residual Urine (volume) |
| Ru | Ready-Use |
| Ru | Recorder Unit |
| Ru | Records Unlimited |
| Ru | Regulatory Unit |
| Ru | Recycled Uranium |
| Ru | Rat Unit |
| Ru | Resistor Unit |
| Ru | Rhutenium |
| Ru | Reproducing Unit |
| Ru | Raviv Ricky Ullman (actor) |
| Ru | Row Uniform |
| Ru | Rubberized Urethane |
| Ru | US Revenue Private Die Playing Card (Scott Catalogue prefix; philately) |