Occult- Unconventional religion. Once a religion becomes conventional, it is no longer considered to be occult. This is known as scientific truth-seeking.
Ophiolatry- Serpent worship. Serpents are associated with fertility, resurrection and immortality.
Oracles- Responses given by a god to a worshipper. They are commonly called answers to prayers. (Ref 1) An oracle is a person or animal that acts as a medium between humans and deities.
