The point of maximum displacement in a wave is called the crest (for a wave with a peak) or trough (for a wave with a valley).

Here's a breakdown:

* Crest: The highest point of a wave, representing the maximum positive displacement from the resting position.

* Trough: The lowest point of a wave, representing the maximum negative displacement from the resting position.

Both crests and troughs represent points of maximum displacement, just in opposite directions.