RSJ – (i) Rolled Steel Joist (construction) RSN – (i) Real Soon Now (coined by author Jerry Pournelle) RSPB – (i) (UK) Royal Society for the Protection of Birds RSPCA – (i) Royal Society for the Prevention of Cruelty to Animals RSR – (i) Required Supply Rate RSRE – (i) UK Royal Signals and Radar Establishment (1976–1991) RSRI – (i) Red Sands Research Institute RSS – (i) Really Simple Syndication RSTA – (i) Reconnaissance, Surveillance, and Target Acquisition RSVP – (i) répondez s'il vous plaît (French for "respond if you please") RT RT (i) Real Time Radio Telephone Respiratory therapist (p) Return to duty RTA – (i) Road traffic accident (British) RTBF – (i) Radio-Télévision belge de la Communauté française (French, "Belgian Radio-Television of the French-speaking Community") RTCA – (i) RTCA, Inc. RTÉ – (i) Raidió Teilifís Éireann RTF – (i) Rich Text Format RTFM – (i) Read the Fucking/Fine Manual RTG (i) Radio-isotope Thermoelectric Generator Rubber Tyred Gantry crane RTGS (a) Royal Thai General System of Transcription Real Time Gross Settlement RTI – (i) Run-Time Infrastructure (Simulation) RTL – see entry RTLS – (a) Return to Launch Site – period in NASA Space Shuttle assent profile where, during assent, shuttle aborts assent and turns and glides back to landing strip at launch site RTPO-RM – (i) Real Time Production Optimization – Reservoir Management RTP – (i) Real-time Transport Protocol RT-PCR – (i) reverse transcriptase polymerase chain reaction (sometimes real-time polymerase chain reaction). Clarified with "quantitative PCR" ("qPCR") or "reverse transcriptase PCR" where appropriate. RTS – see entry RTT – (i) Round Trip Timing RTV – (i) Rapid Terrain Visualization ACTD – Retro Television Network RU ru – (s) Russian language (ISO 639-1 code) Ru – (s) Ruthenium RU – (s) Russia (ISO 3166 digram) RUB – (s) Russian ruble (ISO 4217 currency code) RuBisCO – (p) Ribulose-1,5-bisphosphate carboxylase/oxygenase (enzyme involved in carbon fixation) RUC – (i) Royal Ulster Constabulary run – (s) Rundi language (Kirundi) (ISO 639-2 code) rus – (s) Russian language (ISO 639-2 code) RUS – (s) Russia (ISO 3166 trigram) RUSI – (p) Royal United Services Institute for Defence Studies RV RV (i) Reconnaissance Vehicle Recreational Vehicle Re-entry Vehicle reciprocation void RVD (p) Rijksvoorlichtingsdienst (Dutch, "Government Information Service") (i) Rob Van Dam (American professional wrestler) RW rw – (s) Rwanda language (Kinyarwanda) (ISO 639-1 code) RW – (s) Rwanda (ISO 3166 and FIPS 10-4 country code