A gauge is any device used to measure something, such as a tire pressure gauge or altitude gauge.
The word is also used as a sort of unit of measurement of something, when a simple measurement in, for example, inches or millimeters, is not convenient. In general, higher gauge numbers mean smaller or thinner dimensions, though the exact correspondence depends on the thing being measured and is determined by convention. Things being measured this way include
- Wire diameter
- Medical needles
- Sheet metal thickness
- Gun barrel diameter (shotgun gauge)