accurate
fuel, gas (AmE), oil, petrol (BrE)
depth, pressure, rain, temperature

check, glance at, look at, read
The pilot checked the fuel gauge frequently.

indicate sth, read sth, show sth, tell sb sth
The fuel gauge was reading ‘empty’.
The depth gauge tells you how deep you have dived.

measure sth

broad, narrow, standard

accurate, good, reliable, useful

be seen as, serve as
This company is seen as a gauge of our industrial well-being.

gauge of