From TinWiki.org
The word Zazen is made up of the Japanese word Za, to sit, and zen.
The word Zen comes from the Chinese word ch'am which in turn is a
transliteration of the Sanskrit word dhyana meaning "meditation".
Many forms of sitting meditation existed before the birth of Gautama Buddha.
For instance, the meditation form of Yoga and the likes. In Buddhism one shall be
interested in the practice of sitting in the same position, the same
state of body and mind, as Gautama Buddha. In this posture, Dharma is experienced,
the simple reality that is in front of us, just as it is, without
any filtering by thoughts, hopes, intentions, ambitions, likes and dislikes.