in science and technology RMS (noise reduction) (), a Dolby-B-compatible compander in the former GDR in the 1980s Reconfigurable Manufacturing System, designed for rapid change in its structure Residual mean square, a measure of the difference between data and a model of that data Root mean square, a measure of the magnitude of a varying quantity Royal Microscopical Society thread, or society thread, a screw thread used for microscope objective lenses "Watt RMS", an erroneous term for "average power" used in audio measurements Other uses RMS (band), a British jazz/rock fusion band, formed in 1982 Richard Matthew Stallman, often referred to as "rms", a software freedom activist and computer programmer Royal Mail Ship, the ship prefix used for seagoing vessels that carry mail under contract to the British Royal Mail Resilient Multi-mission Space STaR Shot program, an Australian satellite defence program being developed by Airbus at Lot Fourteen in Adelaide, South Australia