Brainwave entrainment is a technique that uses rhythmic stimuli, such as sound or light, to synchronize brainwave frequencies. This process aims to promote specific mental states, such as relaxation, focus, or sleep, by encouraging the brain to align with the frequency of the external stimulus. Common methods of brainwave entrainment include binaural beats, where two slightly different frequencies are played in each ear, and isochronic tones, which are regular beats of a single tone. These techniques are often used in meditation, stress relief, and cognitive enhancement practices.