Jauge

Jauge is a French term that designates either a measuring instrument or the value indicated by a measurement. Its meaning depends on the context, and it can refer to a device that shows a quantity, level, pressure, thickness, or dimension, or to the capacity or fitting limits of a container or structure.

In technical fields, several types of gauges are commonly encountered. Jauge de niveau measures the level of a liquid in a tank or reservoir. Jauge de pression records the pressure inside a vessel or pipe. Jauge de débit relates to the flow rate or volume of a substance. Jauge d’épaisseur assesses the thickness of materials such as metal sheets or films. There are also gauges used for checking tolerances and producing reference dimensions, sometimes called calibration gauges or gabarits.

In railway terminology, the word is sometimes used to refer to the track gauge—the distance between the rails. This gauge is crucial for compatibility of rolling stock and infrastructure. The standard gauge most widely used is 1,435 millimetres, while other regions employ broader or narrower gauges.

Beyond instrumentation, jauge can denote the nominal capacity of a container or the allowable size in a given system. In metrology and manufacturing, gauges and calipers (calibre) are used to verify dimensions, ensure quality, and maintain uniformity across parts and assemblies.

Etymology traces jauge to the verb jauger, meaning to measure or assess; the noun captures the result or the instrument used to obtain it. The term is closely related to the English word gauge, shared through historical technical vocabulary.