List of acronyms and initialisms: R

This list contains acronyms, initialisms, and pseudo-blends that begin with the letter R.

An acronym is an abbreviation pronounced as a series of constituent letters; an initialism is an abbreviation whose pronunciation is wholly or partly the names of constituent letters; and a pseudo-blend is an abbreviation whose extra or omitted letters means that it cannot be considered a true acronym, initialism, or portmanteau (a word formed by combining two or more words).

(a) = acronym in the example: SARS - (a) Severe acute respiratory syndrome

(i) = initialism in the example: CD - (i) Compact disc

(p) = pseudo-blend in the example: UNIFEM - (p) United Nations Development Fund for Women

(s) = symbol (none of the above, stands for and is read as something else; for example: MHz - Megahertz)

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Please add your own, in a quasi-dictionary order with lowercase treated the same as uppercase and ignoring non-alphanumeric characters (hyphens and such). This means that only alphanumeric characters have any significance in determining order, and that lowercase letters occupy the same ordering position as uppercase (in tie-breaker cases, list lower case first). For example: Algol appears before ALS. (This differs from a strict ASCII ordering.)

• R - (i) Reinforcing - Right - (s) Röntgen
• R2I - (i) Resistance to Interrogation
• R3P - (i) Rearm, Refuel, and Resupply Point

RA

• Ra - (s) Radium
• RA - (s) Rain (METAR Code) - (i) Rear Area - Reinforced Alert - Republican Army - Right Ascension - Royal Artillery (UK)
• RAA - (i) Rear Assembly Area
• RAC - (i) Royal Automobile Club (in the United Kingdom, renamed RAC plc in 2002)
• Radar - (p) RAdio Detection And Ranging
• Racon - (p) RAdar beaCON
• RADC - (i) Region Air Defence Commander
• RAF - (i) Royal Air Force - Red Army Faction
• RAM - (a) Random-Access Memory - Rolling Airframe Missile - Royal Air Maroc
• Ramark - (p) RADar MARKer
• RAOC - (i) Rear Area Operation Centre
• RAP - (i) Recognised [Operating/Operational] Air Picture

RB

• Rb - (s) Rubidium
• R&B - (i) Rhythm and Blues
• RBI - (i) Runs Batted In
• RBOC - (a/i) Regional Bell Operating Company ("Baby Bell")

RC

• RC - see entry
• RCA - (i) Radio Corporation of America - Royal Canadian Artillery - Royal City Avenue (famous entertainment zone in Thailand)
• RCAF - (i) Royal Canadian Air Force
• RCC - (i) Rescue Co-ordination Centre
• RCCO - (i) Royal Canadian College of Organists
• RCMP - (i) Royal Canadian Mounted Police
• RCS - (i) Revision Control System
• RCT - (i) Randomized Controlled Trial
• RCZ - (i) Rear Combat Zone

RD

• RDDL - (a/i) Resource Directory Description Language ("riddle")
• RDECOM - (p) U.S. Research, Development and Engineering Command
• RDV - (i) Remote Detection Vehicle

RE

• Re - (s) Rhenium
• RE - (s) Réunion (ISO 3166 digram)
• REACT - (a) Remote Electronically Activated Control Technology
• REAM - (a) Retired Educators Association of Minnesota
• RERC - (i) Rehabilitation Engineering Research Center
• RES - (i) Radiation Exposure Status - (p) Reserve
• RESNA - (a) Rehabilitation Engineering and Assistive Technology Society of North America
• REU - (s) Réunion (ISO 3166 trigram)

RF

• Rf - (s) Rutherfordium
• RF - (i) Radio Frequency
• RFA - (i) Restrictive Fire Area
• RFC - (i) Request for Comments - Royal Flying Corps (WWI precursor to RAF)
• RFE - (i) Request for Enhancement
• RFID - (p) Radio Frequency IDentification
• RFL - (i) Restrictive Fire Line

RG

• Rg - (s) Roentgenium
• RG - (i) Republican Guard
• RGB - (i) Red Green Blue (colour model)
• RGBI - (i) Red Green Blue Intensity (ditto)

RH

• Rh - (s) Rhodium
• RH - (s) Southern Rhodesia (ISO 3166 digram; obsolete 1980)
• RHIC - (i) Relativistic Heavy Ion Collider
• RHO - (s) Southern Rhodesia (ISO 3166 trigram; obsolete 1980)
• RHU - (i) Replacement Holding Unit
• RHWR - (i) Radar Heading and Warning Receiver ("raw" for short)

RI

• RI - (s) Rhode Island (postal symbol)
• RIAA - (i) Recording Industry Association of America
• RIF - (i) Reduction In Force (layoffs)
• RIP - (a/i) Relief In Place - (i) requiesca[n]t in pace (Latin for "may he/she/they rest in peace")
• RISD - (p) Rhode Island School of Design ("riz-dee")
• RISTA - (a) Reconnaissance, Intelligence, Surveillance, and Target Acquisition (see also ISTAR)

RJ

RK

RL

• RL - (i) Release Line
• RLP - (i) Recognised [Operating/Operational] Land Picture
• RLY - (p) Rally Point

RM

• RMA - (i) Revolution in Military Affairs
• RMDA - (i) Records Management and Declassification Agency
• RMP - (i) Recognised [Operating/Operational] Maritime Picture
• RMS - (i) Rate-Monotonic Scheduling - Richard M. Stallman - Root-Mean-Square - Royal Mail Ship (eg RMS Titanic)

RN

• Rn - (s) Radon
• RNA - (i) RiboNucleic Acid
• RNPS - (i) Radio Network Planning System

RO

• RO - (i) Range Only - (s) Romania (NATO country code; ISO 3166 digram)
• ROC - (i) Regional Operations Centre - Republic of China
• ROD - (a/i) Record Of Decisions
• ROE - (i) Rules Of Engagement
• ROFL(MAO) - (i) Rolling On the Floor Laughing (My A** Off)
• ROM - (a) Read-Only Memory - Refuel On the Move - Royal Ontario Museum
• RO/RO - (a) Roll-On/Roll-Off
• ROU - (s) Romania (ISO 3166 trigram)
• ROV - (i) Remotely Operated Vehicle
• ROW - (i) Rest Of the World
• ROWPU - (a) Reverse Osmosis Water Purification Unit ("roe-pew")
• ROZ - (a/i) Restricted Operations Zone

RP

• RP - (s) Philippines (NATO country code) - (i) Release Point - Role-Playing
• RPG - (i) (US-CA) Regional Planning Group - Rocket Projectile Gun - Rocket-Propelled Grenade - Role-Playing Game
• RPL - (i) Reverse Polish Lisp
• rpm - (s) revolutions per minute
• RPM - (i) Red Hat Package Manager
• RPN - (i) reverse Polish notation
• RPR-FOM - (i) Realtime Platform Reference Federation Object Model
• rps - (s) revolutions per second
• RPV - (i) Remotely Piloted Vehicle

RQ

• RQ - (s) Puerto Rico (NATO country code)

RR

• RRN - (i) Recurrence Rate Number
• RRS - (i) Racing Rules of Sailing
• RRSP - (i) Registered Retirement Savings Plan (Canada; roughly equivalent to the IRA in the U.S.)

RS

• RS - (s) Russia (NATO country code)
• R&S - (i) Reconnaissance & Surveillance
• RSA - (i) Regimental Support Area
• RSI - (i) Repetitive Strain Injury
• RSJ - (i) Rolled Steel Joist (construction)
• RSN - (i) Real Soon Now (coined by author Jerry Pournelle)
• RSPCA - (i) Royal Society for the Prevention of Cruelty to Animals
• RSR - (i) Required Supply Rate
• RSS - (i) Really Simple Syndication
• RSVP - (i) répondez s'il vous plaît (French for "please reply")

RT

• RT - (i) Real Time - (p) Return to duty
• RTBF - (i) Radio-Télévision belge de la Communauté française
• RTÉ - (i) Radio Telefís Éireann
• RTF - (i) Rich Text Format
• RTFM - (i) Read the Fucking/Fine Manual
• RTL - see entry
• RTP - (i) Real-time Transport Protocol
• RTS - see entry
• RTT - (i) Round Trip Timing

RU

• Ru - (s) Ruthenium
• RU - (s) Russia (ISO 3166 digram)
• RUC - (i) Royal Ulster Constabulary
• RUS - (s) Russia (ISO 3166 trigram)

RV

• RV - (i) Recreational Vehicle - Re-entry Vehicle

RW

• RW - (s) Rwanda (NATO country code; ISO 3166 digram)
• RWA - (s) Rwanda (ISO 3166 trigram)
• RWADA - (a) Resident Weighted Average Daily Attendance (New York State term used in public education to indicate the size of a school district, i.e its number of students)

RX

• Rx - (s) Medical prescription
• RX - (s) Receive

RY

RZ

See also

• List of acronyms and initialisms