To relax means to calm the mind, the body or both.
I think it's very important to understand that relaxation
is a state that can be achieved voluntarily and it starts in your brain.
Relaxation is a relief from bodily or mental work, effort;
it's a loosening or slackening, a diminution of strictness or severity.
Relaxation is the return of your body to an initial state of equilibrium after
it went through an abrupt periodic disturbance. It's refreshment of body or mind.
Relaxing can quiet your mind and make you feel peaceful and calm.
Your body also reacts when you relax.
For instance your muscles may be less tense and more flexible.
Relaxation massage is a way to reduce the body's stress response.