Meditation is a technique for producing an altered state of consciousness. It usually involves sitting still for a period during which consciousness might be focused by means of a word repeated silently in the mind, or by the visualization of an image of some sort. The Vipassana, or insight, meditation practiced by Buddhists stresses mere observation of what takes place in the mind and body during meditation.
Christian meditation is a form of silent, contemplative prayer that uses a prayer-word, which is rooted in the gospel and the letters of St. Paul, and originated with the early desert fathers of the fourth century. It is a daily personal discipline, a practice of stillness and simplicity, not a substitute for all the other forms of prayer, but as a center for them.