ball cock

American  

Or ballcock

noun

1. a device for regulating the supply of water in a tank, cistern, or the like, consisting essentially of a valve connected to a hollow floating ball which by its rise or fall shuts or opens the valve.

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ball cock British  

noun

1. a device for regulating the flow of a liquid into a tank, cistern, etc, consisting of a floating ball mounted at one end of an arm and a valve on the other end that opens and closes as the ball falls and rises with the water level in the cistern

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Etymology

Origin of ball cock

First recorded in 1780–90

Example Sentences

On top of the generator is a tipping water-bucket I supplied with water through a ball cock.

From Acetylene, the Principles of Its Generation and Use A Practical Handbook on the Production, Purification, and Subsequent Treatment of Acetylene for the Development of Light, Heat, and Power by Leeds, F. H. (Frank Henley)

To prevent their freezing when full of water, preserve a little circulation by leaving the cock dripping; or by tying up the ball cock during the winter's frost, the water may be preserved for use.

From The Cook and Housekeeper's Complete and Universal Dictionary; Including a System of Modern Cookery, in all Its Various Branches, Adapted to the Use of Private Families by Eaton, Mary, fl. 1823-1849