Meaning of ball valve

ball' valve"

Pronunciation: [key]
— Mach. Mach.
  1. a valve controlling flow by means of a ball pierced with an opening in one direction and fixed to rotate on a spindle at right angles to the opening.
  2. any valve that checks flow by the seating of a ball.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.