'''IR''' or '''Ir''' may refer to: {{TOC right}}
==Arts and media== * Ir (newspaper), Latvian weekly newspaper * ''Imperator: Rome'', a 2019 video game published by Paradox Interactive * Integrated resort, a euphemism for a casino in Singapore * ''International Relations'' (journal), an academic journal * I.R. Baboon, a fictional character in the cartoon series ''I Am Weasel''
==Businesses and organizations== ===Transportation=== * Iarnród Éireann (Irish Rail), national passenger and freight railway system of the Republic of Ireland * Illinois Railway, US * Indian Railways, state-owned railway company of India * InterRegio, part of Swiss Federal Railways * IR Ishikawa Railway, local railway company in Ishikawa, Japan * Iran Air (IATA airline code IR) * Israel Railways, state-owned railway company of Israel
===Other businesses and organizations=== * Ingersoll Rand (NYSE trading symbol IR) * International Rectifier, a former manufacturer of power semiconductors * Independent-Republican Party of Minnesota, former name of the Republican Party of Minnesota
==Finance== *Incidence rate (market research) *Interest rate, or (when referring to an asset class) interest rate derivative * Information ratio, when referring to risk-adjusted returns of a financial security * Investor relations, a management responsibility in which companies disclose information for regulatory compliance and for bond/share-holders to make investment judgments
==Language== * Ir (cuneiform), a sign in cuneiform writing * Ir language, also known as Ta'Oi language, spoken in parts of Laos and Vietnam * Istro-Romanian language
==Places== * Indian Reserve, a section of land in Canada that is controlled by an Indigenous band government * Iran, by ISO country code
==Science and technology== ===Biology and medicine=== * Immediate-release, related to time release technology in pharmaceuticals * Incidence Rate, in epidemiology * Insulin receptor, a transmembrane receptor that is activated by insulin * Insulin resistance, a pathological condition * Interventional radiology and interventional radiologist, an independent medical specialty * Inverted repeat, a sequence of nucleotides that is the reversed complement of another sequence further downstream
===Computing=== * .ir, the Internet country code top-level domain for Iran * Adobe ImageReady, a bitmap graphics editor shipped with Adobe Photoshop by Adobe Systems * Image retention, the LCD and plasma display equivalent of screen burn * Information retrieval, the science of searching for information in or as documents or databases * Information revolution, one of the theoretical frameworks within which trends in current society can be conceptualized * Institutional repository, a digital collection for preserving the intellectual output of an institution * Institutional research, the collection, analysis, and reporting of institutional data * Instruction register, part of a CPU's control unit * Intermediate representation, a computer data structure * Internal router
===Other uses in science and technology=== * Imaginary numbers, in mathematics, denoted <math>\text{i}\mathbb{R}</math> or {{math|i'''R'''}} * Infrared, a portion of the electromagnetic radiation spectrum * Impulse response, an output function of a dynamic system presented with a brief input signal * Insulation resistance, a measure of insulation material performance * Ionizing radiation * Iridium, symbol Ir, a chemical element
==Other uses== * Imperial–royal, abbreviation applied to institutions of the Austrian Empire * Industrial relations, relations between management and workers in industry * Ingenieur, abbreviated ''ir.'', an engineer's degree awarded by technical universities in the Netherlands, Belgium, Indonesia, and Malaysia * Injured reserve list, a list of professional sports players who are injured and unable to play for an extended time * International relations, in political science, the study of foreign affairs of and relations among states * International rules football a hybrid code of football
==See also== * <math>\mathbb{R}</math>, the symbol of the set of real numbers in mathematics * Inland Revenue Department (disambiguation), a government revenue service in several countries * International Rescue (disambiguation) * IRS (disambiguation)
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