Definition: A millivolt-ampere reactive (mVAR) is a unit of measurement for reactive power, equal to one-thousandth of a VAR (Volt-Ampere Reactive). It is used to quantify smaller amounts of reactive power in AC electrical systems.

History/origin: The millivolt-ampere reactive (mVAR) is a derivative of the VAR (Volt-Ampere Reactive), which arose from the understanding of reactive power in AC systems in the late 19th century. The 'milli-' prefix denotes a factor of 10^-3, making mVAR suitable for measuring smaller reactive power quantities.

Current use: mVARs are used in applications where precise measurement of small reactive power quantities is needed, such as in electronic circuits, power electronic devices, and specialized equipment. They can also be used in detailed power system analysis and simulation studies.