The American Heritage® Dictionary of the English Language, 4th Edition
n. The belief, based solely on reason, in a God who created the universe and then abandoned it, assuming no control over life, exerting no influence on natural phenomena, and giving no supernatural revelation.
n. A philosophical belief in the existence of a god (or goddess) knowable through human reason; especially, a belief in a creator god unaccompanied by any belief in supernatural phenomena or specific religious doctrines.
the GNU version of the Collaborative International Dictionary of English
n. The doctrine or creed of a deist; the belief or system of those who acknowledge the existence of one God, but deny revelation.
The Century Dictionary and Cyclopedia
n. The doctrine that God is distinct, and separated from the world. See deist, 1.
n. Belief in the existence of a personal God, accompanied with the denial of revelation and of the authority of the Christian church.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the form of theological rationalism that believes in God on the basis of reason without reference to revelation
Word Usage
"Most people have probably never heard of the term deism, or, if they had, would fail to distinguish it from theism."