QR may refer to:

Arts and entertainment

Nippon Cultural Broadcasting is a Japanese radio station in Tokyo which broadcasts to the Kanto area. It is one of the two flagship radio stations of National Radio Network (NRN) (the other station is ) and is a member of the Fujisankei Communications Group. History The ...

(from call sign JOQR), a Tokyo radio station * Queen's Radio, a student radio station at Queen's University Belfast *

Quiet Riot Quiet Riot is an American heavy metal music, heavy metal band founded in Los Angeles in 1973 by guitarist Randy Rhoads, bassist Kelly Garni, and vocalist Kevin DuBrow. The original lineup featured Rhoads and Garni with lead vocalist Kevin Du ...

, an American rock band

Businesses

Qatar Airways Qatar Airways Company Q.C.S.C. (, ''al-Qaṭariyya''), operating as Qatar Airways, is the flag carrier of Qatar. Headquartered in the Qatar Airways Tower in Doha, the airline operates a hub-and-spoke network, flying to over 170 internatio ...

(IATA code) *

Queensland Rail Queensland Rail (QR) is a railway operator in Queensland, Australia. Queensland Rail is owned by the Queensland Government, and operates both Commuter rail, suburban and Regional rail, interurban rail services in South East Queensland, as well ...

, a company responsible for the railway system in Queensland, Australia *

Quintana Roo (company) Quintana Roo (QR) was the first company to create a triathlon-specific wetsuit over 25 years ago, and then a tri-specific bicycle two years later. The company was founded in 1987 by Dan Empfield of Ironman fame and is currently owned by the Am ...

, a triathlon-specific wetsuit and bicycle company

Places

Quintana Roo Quintana Roo, officially the Free and Sovereign State of Quintana Roo, is one of the 31 states which, along with Mexico City, constitute the 32 administrative divisions of Mexico, federal entities of Mexico. It is divided into municipalities of ...

, a state of Mexico *

Karakalpakstan Karakalpakstan, officially the Republic of Karakalpakstan, is an autonomous republic and part of Uzbekistan. It spans the northwestern portion of Uzbekistan. Its capital is Nukus (' / ). Karakalpakstan has an area of , and has a population of a ...

(Qoraqalpog'iston Respublikasi), Uzbekistan (ISO 3166-2 subcode UZ-QR)

Science and technology

* QR code (Quick Response code), a two-dimensional code * ATCvet code QR ''Respiratory system'', a section of the Anatomical Therapeutic Chemical Classification System for veterinary medicinal products * DICOM Q/R,

DICOM Digital Imaging and Communications in Medicine (DICOM) is a technical standard for the digital storage and Medical image sharing, transmission of medical images and related information. It includes a file format definition, which specifies the str ...

Query / Retrieve *

Nissan QR engine The QR family of inline-four piston engines by Nissan were introduced in 2000 and range from in displacement. These motors are aluminum, dual overhead camshaft (DOHC), four-valve designs with variable valve timing and optional direct injection. ...

Quarter (unit) The quarter ( "one-fourth") was used as the name of several distinct English units based on ¼ sizes of some base unit. The "quarter of London" mentioned by ''Magna Carta'' as the national standard measure for wine, ale, and grain was ¼ ton o ...

** qr., , of a yard, equal to 9 inches ** qr. av., , of a hundredweight, equal to 2 stone or 28 pounds avoirdupois

Mathematics

QR decomposition In linear algebra, a QR decomposition, also known as a QR factorization or QU factorization, is a decomposition of a matrix ''A'' into a product ''A'' = ''QR'' of an orthonormal matrix ''Q'' and an upper triangular matrix ''R''. QR decom ...

, a decomposition of a matrix **

QR algorithm In numerical linear algebra, the QR algorithm or QR iteration is an eigenvalue algorithm: that is, a procedure to calculate the eigenvalues and eigenvectors of a Matrix (mathematics), matrix. The QR algorithm was developed in the late 1950s by John ...

, an eigenvalue algorithm to perform QR decomposition *

Quadratic reciprocity In number theory, the law of quadratic reciprocity is a theorem about modular arithmetic that gives conditions for the solvability of quadratic equations modulo prime numbers. Due to its subtlety, it has many formulations, but the most standard st ...

, a theorem from modular arithmetic *

Quasireversibility In queueing theory, a discipline within the mathematical theory of probability, quasireversibility (sometimes QR) is a property of some queues. The concept was first identified by Richard R. Muntz and further developed by Frank Kelly. Quasireversib ...

, a property of some queues *

Reaction quotient In chemical thermodynamics, the reaction quotient (''Q''r or just ''Q'') is a dimensionless quantity that provides a measurement of the relative amounts of products and reactants present in a reaction mixture for a reaction with well-defined overal ...

(Q_r), a function of the activities or concentrations of the chemical species involved in a chemical reaction

Other uses

* ''

Quarterly Review The ''Quarterly Review'' was a literary and political periodical founded in March 1809 by London publishing house John Murray. It ceased publication in 1967. It was referred to as ''The London Quarterly Review'', as reprinted by Leonard Scott, f ...

'', a defunct literary and political periodical *

Qatari riyal The Qatari riyal (currency sign, sign: QR in Latin alphabet, Latin, in Arabic script, Arabic; ISO 4217, ISO code: QAR) is the official currency of the Qatar, State of Qatar. It is divided into 100 dirhams (). History Until 1966, Qatar used t ...