- the hammering sound caused in a pipe containing water when live steam is passed through it
- the thump of water in a pipe, caused by an air lock, when a faucet is suddenly closed
See water hammer in American Heritage Dictionary 4
- A banging noise heard in a water pipe following an abrupt alteration of the flow with resultant pressure surges.
- A banging noise in steam pipes, caused by steam bubbles entering a cold pipe partially filled with water.