RR, Rr or rr may refer to:

Arts and entertainment

* ''RR'' (film), a 2007 experimental film by James Benning * Red Ribbon Army, a fictional army in the ''Dragon Ball'' series * Ruff Ryders Entertainment, a record label and East Coast rap collective * ''

Fury from the Deep ''Fury from the Deep'' is the Doctor Who missing episodes, completely missing sixth serial of the Doctor Who (season 5), fifth season in the British science fiction television series ''Doctor Who'', which originally aired in six weekly parts from 1 ...

'' (production code: RR), a 1968 ''Doctor Who'' serial * ''RR'' (EP), a 2023 collaborative EP by Rosalía and Rauw Alejandro * RR, prefix for models of Jackson Rhoads electric guitars commissioned by guitarist Randy Rhoads

Businesses and organizations

* Rashtriya Rifles, an Indian counter-insurgency force * Rational Recovery, an addiction recovery program * Rekords Rekords (logo), an American record label * Rhodesia Regiment, Rhodesian Army unit *

Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...

(IATA airline designator) * Richard Rohac (logo), an Austrian art metal firm

Language

* rr (digraph) *

Revised Romanization of Korean Revised Romanization of Korean () is the official Romanization of Korean, Korean language romanization system in South Korea. It was developed by the National Institute of Korean Language, National Academy of the Korean Language from 1995 and w ...

, the official Korean language romanization system in South Korea * Revised Romanization of Hangeul, the former official Hangeul language romanization system in South Korea

Science and technology

ITU Radio Regulations The ITU Radio Regulations (RR) is a basic document of the International Telecommunication Union (ITU) that regulates on law of nations scale radiocommunication services and the utilisation of radio frequencies. It is the supplementation to th ...

* Rapid Refresh (weather prediction), a short-range numerical weather prediction model *

Rear-engine, rear-wheel-drive layout In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bum ...

, in automotive design * Recoilless rifle

Biology and medicine

* RR, an Rh factor phenotype * "RR", a blood pressure measurement taken with a sphygmomanometer invented by Scipione Riva-Rocci * RR interval (R wave to R wave interval), the inverse of heart rate *

Risk ratio The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio, relative risk measures the association bet ...

, or relative risk, in statistics and epidemiology *

Respiratory rate The respiratory rate is the rate at which breathing occurs; it is set and controlled by the respiratory center of the brain. A person's respiratory rate is usually measured in breaths per minute. Measurement The respiratory rate in humans is mea ...

, a vital sign *

Roundup Ready Roundup Ready is the Bayer (formerly Monsanto) trademark for its patented line of genetically modified crop seeds that are resistant to its glyphosate-based herbicide, Roundup (herbicide), Roundup. History In 1996, genetically modified ''Roundup ...

, Monsanto line of genetically modified crop seeds

Computing

* Resource record, in the Domain Name System *

Round-robin scheduling Round-robin (RR) is one of the algorithms employed by process and network schedulers in computing. Guowang Miao, Jens Zander, Ki Won Sung, and Ben Slimane, Fundamentals of Mobile Data Networks, Cambridge University Press, , 2016. As the term ...

, an algorithm for coordinating processes in an operating system * Route reflector, a Border Gateway Protocol configuration * rr (debugging), a record and replay debugger for userspace Linux programs * Resurrection Remix OS, a custom Android ROM created by Altan KRK and Varun Date

Sports

* Rajasthan Royals, an Indian Premier League franchise * Ranchi Rhinos, a defunct Hockey India League franchise *

Run rate In cricket, the run rate (RR), or runs per over (RPO), is the average number of runs a batting side scores per over. It includes all runs made by the batting side in the innings to that point of the game, both the runs scored by the batsmen an ...

, an average number of runs a batsman (or the batting side) scores in an over of 6 balls in cricket

Transportation

Raritan River Railroad The Raritan River Rail Road was a shortline railroad in Middlesex County, New Jersey, Middlesex County in the U.S. state of New Jersey, Founded in 1888, it was based in South Amboy, New Jersey, South Amboy, from which it ran west as far as Ne ...

(reporting mark: RR) *

Buzz (Ryanair) Buzz is a Polish airline headquartered in Warsaw. Formerly called Ryanair Sun, it is a subsidiary of the Irish airline company Ryanair Holdings and a sister airline to Ryanair DAC, Ryanair UK, Malta Air and Lauda Europe. Formed in 2017 and i ...

(IATA code: RR), a Polish airline subsidiary of Ryanair Holdings * Regional Road, a class of road in Ontario * Rhodesia Railways, former Zimbabwean railway company *

Rhymney Railway The Rhymney Railway (RR) was a railway company in South Wales, founded to transport minerals and materials to and from Colliery, collieries and ironworks in the Rhymney Valley of South Wales, and to docks in Cardiff. It opened a main line in 18 ...

, former British railway company *

Rolls-Royce Holdings Rolls-Royce Holdings plc is a British Multinational corporation, multinational aerospace and defence company incorporated in February 2011. The company owns Rolls-Royce, a business established in 1904 which today designs, manufactures and dist ...

(LSE code and logo) **

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...

, several companies * RR, a predecessor of the R (New York City Subway service)