Simple Harmonic Motion or SHM is defined as a motion in which the restoring force is directly proportional to the displacement of the body from its mean position.
When the oscillator's energy is reduced as a result of an external force, the oscillator is said to be damped.
In a damped simple harmonic motion, the oscillator's energy gradually decreases.
These simple harmonic motions are damped periodic motions of gradually diminishing amplitude as well as energy.
A simple pendulum is an example of a damped simple harmonic motion.