Theism is broadly defined as the belief in the existence of at least one deity. In common parlance, or when contrasted with deism, the term often describes the philosophical conception of God that is found in classical theism—or the conception found in monotheism—or gods found in polytheistic religions—or a belief in God or gods without the rejection of revelation, as is characteristic of deism.
Non-theism and atheism is commonly understood as non-acceptance or outright rejection of theism in the broadest sense of the term (i.e., non-acceptance or rejection of belief in God or gods). Related (but separate) is the claim that the existence of any deity is unknown or unknowable; a stance known as agnosticism. Agnostic theism is a personal belief in one or more deities along with acceptance that the existence or non-existence of the deity or deities is fundamentally unknowable.