| Acronym | Definition |
|---|
| IR➣Infrared |
| IR➣Iran |
| IR➣International Relations |
| IR➣Imposto de Renda (Brazil) |
| IR➣Investor Relation |
| IR➣Injured Reserve (football) |
| IR➣Intermediate Representation |
| IR➣Irish (linguistics) |
| IR➣Immune Response |
| IR➣Islamic Republic of Iran (ISO country code, top level domain) |
| IR➣Information Required |
| IR➣Interest Rate (economics) |
| IR➣Institutional Research |
| IR➣Ingersoll-Rand (pneumatic products company) |
| IR➣Islamic Republic |
| IR➣Engineer (University, Dutch) |
| IR➣Inland Revenue (UK) |
| IR➣Islamic Relief (UK) |
| IR➣Insulation Resistance |
| IR➣Image Runner |
| IR➣Information Retrieval |
| IR➣Industrial Relations |
| IR➣Institutional Repository (digital intellectual output) |
| IR➣Insulin Resistance |
| IR➣Instrument Rating (Aviation) |
| IR➣Indian Reservation |
| IR➣Infrared Radiation |
| IR➣Immediate Release (pharmaceutics) |
| IR➣Impôt sur le Revenu (French income tax) |
| IR➣Impulse Response (radio propagation) |
| IR➣Indian Railway |
| IR➣Iridium |
| IR➣Information Resources |
| IR➣Interface Repository |
| IR➣Instruction Register |
| IR➣Independent Research |
| IR➣Insulin Receptor (molecular biology) |
| IR➣Information Request |
| IR➣Incident Response (security) |
| IR➣Incidence Rate |
| IR➣Initial Response (military logistics) |
| IR➣Ingenieur (Dutch: Master of Science) |
| IR➣Inspection Report |
| IR➣Incident Report (Canadian Air Force) |
| IR➣Information Requirements |
| IR➣Information Report(s) |
| IR➣Ionizing Radiation |
| IR➣Interventional Radiology (medicine) |
| IR➣Internal Resources |
| IR➣Inter-Research |
| IR➣Industrial Robot |
| IR➣Im Ruhestand (German: Retired) |
| IR➣Insuficiencia Renal (Spanish: Renal Failure) |
| IR➣Information Revolution |
| IR➣Imaging Radar |
| IR➣Information Ratio |
| IR➣Ischaemia-Reperfusion |
| IR➣Instant Replay |
| IR➣International Roaming (GSM technology) |
| IR➣Internal Review |
| IR➣Iran Air (IATA airline code) |
| IR➣Information Repository (US EPA Superfund site information) |
| IR➣Information Rate (US DoD) |
| IR➣Issue Resolution (various organizations) |
| IR➣Internal Resistance |
| IR➣Intelligence Report |
| IR➣Initialization and Refresh (compressor state) |
| IR➣Internet Registry |
| IR➣Ingestion Rate |
| IR➣Index Register |
| IR➣Infrared Radiometer |
| IR➣Information Record |
| IR➣Interrupt Request |
| IR➣Independent Radio |
| IR➣Investigation Report |
| IR➣Iron Rod |
| IR➣Inherited Runner (baseball; runner on base when a pitcher enters) |
| IR➣Integrated Resort (Singapore) |
| IR➣Internal Rotation |
| IR➣Interventional Radiologist (medicine) |
| IR➣Impairment Rating (medical assessment) |
| IR➣Intermediate Reach |
| IR➣Inner Radius (construction industry) |
| IR➣InterRegio (train) |
| IR➣Incident Record |
| IR➣Intelligent Routing (computing) |
| IR➣Inhalation Rate |
| IR➣Installation Restoration |
| IR➣Ileal Resection |
| IR➣Ice on Runway |
| IR➣Intelligence Requirement (US DoD) |
| IR➣Internet Router |
| IR➣Isoprene Rubber (polyisoprene rubber) |
| IR➣Iterative Reconstruction |
| IR➣Isoprene Rubber |
| IR➣Image Rejection (radio electronics) |
| IR➣Interracial Relationship |
| IR➣Interference Rejection (communications systems) |
| IR➣Incremental Reactivity |
| IR➣Ivan Reitman (film director) |
| IR➣Installation Report |
| IR➣Instrument Reading |
| IR➣Invoice Receipt (accounting) |
| IR➣Integrated Resources |
| IR➣Israel Railways |
| IR➣Inspection Record |
| IR➣Institut de Rééducation (French: Rehabilitation Institute; various locations) |
| IR➣International Rendezvous (dating service) |
| IR➣Interstate Route |
| IR➣Inspection Request (construction) |
| IR➣Investigation Request |
| IR➣Industrial Roundtable |
| IR➣InterReklama (Russian advertising network) |
| IR➣Invitation Request |
| IR➣Intensification Ratio |
| IR➣Indigenous Revolution |
| IR➣Inward Radial |
| IR➣Interval Rate |
| IR➣Investment Request |
| IR➣Internal Revision |
| IR➣Integrated Rating (marine) |
| IR➣Internment/Resettlement |
| IR➣Instrument Route |
| IR➣Interoperability Requirement |
| IR➣Ingress Router |
| IR➣Intelligence Request |
| IR➣Intermediate Resonance |
| IR➣IFR Military Training Route |
| IR➣Interposing Relay |
| IR➣Investable Resources |
| IR➣Intelligent Roaming |
| IR➣Intermittent Reperfusion |
| IR➣Intermediate Rear |
| IR➣Induction Regulator |
| IR➣Interruption Reporting |
| IR➣IglooReport (Pittsburgh Penguins website) |
| IR➣Imperator et Rex (Emperor and King) |
| IR➣Internet Protocol Detail Record Recorder |
| IR➣Incoherent Recombining |
| IR➣Incorrect Reconfiguration |
| IR➣Inhibiting Relay |
| IR➣Insurance Record(s) (insurance) |
Ir - a heavy brittle metallic element of the platinum group; used in alloys; occurs in natural alloys with platinum or osmium