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 \text{i}\mathbb{R} or •
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==