A gauge, in science and engineering, is a device used to make measurements or in order to display certain dimensional information. A wide variety of tools exist which serve such functions, ranging from simple pieces of material against which sizes can be measured to complex pieces of machinery.
Gauges are old measures of thickness. They originated in the British iron wire industry at a time when there was no universal unit of thickness. ... Gauges were measured and described in fractions of an inch during the 19th century. In the UK, one gauge was standardised and legally enforced as the Standard Wire Gauge.