What is the trough in a wave?

A trough in a wave refers to the lowest point that the wave reaches. In the context of wave motion, whether it be sound waves, light waves, or water waves, the trough represents the point where the displacement of the medium (such as air or water) is at its minimum value relative to the equilibrium position.

On a wave diagram, the trough is often depicted as the downward peak, contrasting with the crest, which is the highest point of the wave. This concept is crucial for understanding wave properties such as amplitude, wavelength, and the energy carried by the wave. Recognizing the trough helps in visualizing how energy propagates through different mediums and contributes to the overall behavior of waves.