Meditation is a technique to train the mind where to direct its focus, to become more aware and free of the inner dialogue. It usually results in a mentally clearer, emotionally more calm and stable state.
There are many forms of meditation, each with its particular set of instructions. A lot of meditation research has been conducted in the last decades.
Meditation has been shown to reduce stress, perception of pain, anxiety, and depression in most subjects.
Some people find meditation easy, others need a lot of practice to be able to witness or quiet their thought processes.