gauge

gauge 1

•  noun [C]

1    an instrument that measures the amount or size of something:
?a fuel gauge

2    a standard that you use to decide what a situation is like:
?gauge of: Money is not the only gauge of success.
3    the thickness of something such as a piece of metal

gauge 2

• verb [T]

1    to decide what someone's feelings, intentions etc probably are:
?a study to gauge public reaction to the proposed changes
?gauge whether/how etc: I couldn't gauge how he felt from the look on his face.
2    to measure something using a particular instrument or method