Vibratory motion:

            To and fro motion of a body about its mean position is known as vibratory motion.

Examples:

Consider the motion of a baby about in a swing. As it is pushed, the swing moves back and forth about its mean position. The motion of the baby repeats from one extreme to the other extreme with the swing. Such a type of motion is called vibratory motion.

To and fro the motion of the pendulum of a clock about its mean position, is called vibratory motion.

A baby in a cradle moving to and fro, to and fro motion of the hammer of a ringing electric bell and the motion of the string of a sitar are some of the examples of vibratory motion.