Definition of sight glass in US English:

sight glass


  • A transparent tube or window through which the level of liquid in a reservoir or supply line can be checked visually.

    • ‘On some equipment, a visual sight glass or gauge shows fluid levels without opening the system, while on others a dipstick or other manual measuring device is used.’
    • ‘The sight glasses on the Mighty Demon's fuel howls permit safe, quick, float-level adjustments without the risk of fuel spillage.’
    • ‘Babette pointed a red fingernail to the sight glass of the brass lubricator.’
    • ‘An oil level sight glass, a tank pressure gauge and, of course, a pressure regulator and gauge are important, as each tool and job has a specific pressure requirement.’
    • ‘The fuel bowls also feature a clear sight glass for fuel level verification and adjustment.’