Beats can be defined as the periodic variation in the intensity of sound at a given point due to superposition of two waves having slightly different frequencies.
EXPLANATION WITH EXAMPLE
If two tuning forks of slightly different frequencies are set to vibrate simultaneously, we hear a sound and low intensity. This is called a beat and phenomenon is called Beats.
Beat frequency is the no of beats one hear in one second. It is defined as the difference infrequency b/w two sounds.
The maximum beat frequency that a human ear can detect is 7 beats/seconds.