water glass

noun
  1. 1

    A drinking vessel intended or used for water.

    โ€œShe asked the server to refill her water glass.โ€

  2. 2

    Any of various water-soluble silicate compounds, especially when occurring in dissolved, jelly-like form.

  3. 3

    A water gauge for a steam boiler.

  4. 4

    An instrument consisting of an open box or tube with a glass bottom, used for examining objects in the water, as upon the sea bottom in shallow places.

  5. 5

    A water clock.

Source: https://en.wiktionary.org/wiki/water%20glass