the·ism (thē'ĭz'əm) n. Belief in the existence of a god or gods, especially belief in a personal God as creator and ruler of the world. the'ist n., the·is'tic, the·is'ti·cal adj., the·is'ti·cal·ly adv.
1662, from Gk. theos "god" (see Thea) + -ist. The original senses was that later reserved to deist: "one who believes in a transcendant god but denies revelation." Later in 18c. theist was contrasted with deist, as allowing the possibility of revelation. Theism "belief in a deity" is recorded from 1678; meaning "belief in one god" (as opposed to polytheism) is recorded from 1711. Theistic is attested from 1780.
[thee-iz-uh
m] 
