/ Dictionary / Index B ball cock: Meaning and Definition of Find definitions for: ball' cock" Pronunciation: [key] 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. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ballcock (Thesaurus) ball club ball control Related Content Daily Word Quiz: blanch Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language