Frequency in the context of sound waves refers to the number of compressions or rarefactions that pass a point in the medium per unit time.

The SI unit of wavelength is meter (m), and it is commonly represented by the Greek letter λ (lambda).

The distance between two consecutive compressions or rarefactions is called the wavelength.

Peaks are the highest points of a wave and are called crests, while valleys are the lowest points of a wave and are called troughs.

Compressions are regions where both density and pressure are high, while rarefactions are regions of low pressure where particles are spread apart.