Gauge
1) A numerical system that designates nominal wire diameter. The various standards in use (e.g., American Wire Gage (AWG), the United States Standard Gage (USS), Galvanized Sheet Gage (GSG), the Birmingham Wire Gage (BWG), etc.) are arbitrary in nature and differ between ferrous and nonferrous wires. 2) An instrument used to measure diameter or length. 3) An aid for visual inspection, which enables the inspector to determine more reliably whether the size or contour of a formed part meets dimensional requirements. Sometimes spelled as gage.