The belief in the existence of a supreme being, specifically of a creator who does not intervene in the universe. The term is used chiefly of an intellectual movement of the 17th and 18th centuries that accepted the existence of a creator on the basis of reason but rejected belief in a supernatural deity who interacts with humankind.
Deism is not a specific religion but rather a particular perspective on the nature of God. Deists believe that a creator god does exist, but that after the motions of the universe were set in place he retreated, having no further interaction with the created universe or the beings within it. As such, there are a variety of common religious beliefs that deists do not accept. http://altreligion.about.com
Deism is the belief in a God who created the world but hasn't gotten involved with people since then - as opposed to theism, whose God still takes an active role in the world.
Deism - Religious philosophy - by: David A. Pailin
Deism, an unorthodox religious attitude that found expression among a group of English writers beginning with Edward Herbert (later 1st Baron Herbert of Cherbury) in the first half of the 17th century and ending with Henry St. John, 1st Viscount Bolingbroke, in the middle of the 18th century. These writers subsequently inspired a similar religious attitude in Europe during the second half of the 18th century and in the colonial United States of America in the late 18th and early 19th centuries. In general, Deism refers to what can be called natural religion, the acceptance of a certain body of religious knowledge that is inborn in every person or that can be acquired by the use of reason and the rejection of religious knowledge when it is acquired through either revelation or the teaching of any church.
Deism is therefore a natural religion and is not a "revealed" religion.