Here's a breakdown:

* Wave: A disturbance that travels through a medium or space, transferring energy without transferring matter.

* Identical points: These could be crests (highest points), troughs (lowest points), or any other corresponding points on the wave cycle.

* Wavelength: The distance between two consecutive identical points on a wave.

For example, the wavelength of a sound wave is the distance between two consecutive compressions (high pressure areas) or rarefactions (low pressure areas). The wavelength of a light wave is the distance between two consecutive crests or troughs.