Frequency( n): The number of waves produced in one second  (or) number of waves passing through a point in a medium in one second (or) When a wave is passing through a medium the number of oscillations made by any particle of the medium in one second , is called frequency.

Wave length ( λ ): The distance between two successive crests or two successive troughs or distance between two successive compressions or distance between two successive rarefactions is called wave length.

The distance between two points in phase with one another , in   successive waves is called wave length.

Amplitude (A) : Maximum displacement of any point in the medium, when a wave is passing through  it  is called amplitude of the wave or amplitude of oscillation.