IRM may refer to: IERS Reference Meridian. Illinois Railway Museum. Illinois Reserve Militia, state defense force active during World War II. Bureau of Information Resource Management, responsible for information technology of the U.S. Department of State. Information Rights Management. Intermediate Restorative Material (Dentistry) Zinc oxide eugenol. L'Institut Royal Météorologique de Belgique. Interference reflection microscopy, a microscopy method used to image adherent cells.
https://en.wikipedia.org/wiki/IRM