The pounding or banging of pipes and shuddering of fixtures caused by a shock wave resulting from a sudden stop of water flow in a pipe is:

Water hammer is a phenomenon that occurs when a fluid in motion is forced to stop or change direction suddenly, creating a shock wave within the piping system. This can happen when a valve closes quickly or if there’s a sudden change in the flow of the liquid. The rapid deceleration of the water creates pressure waves that can cause banging or pounding sounds in pipes, leading to vibration and even potential damage to fixtures and the piping system.

The term "water hammer" succinctly captures the essence of this mechanical shock wave and its consequential effects on the plumbing infrastructure. Properly designed systems include measures such as air chambers or surge tanks to mitigate such occurrences, which highlights the importance of understanding this concept in power engineering and plumbing applications.