The study or science of the devil; the branch of theology dealing with evil and demonic forces.
From diabolo- (relating to the devil) + -logy (from Greek logos, discourse or study), a more formal or technical variant of diabology, possibly influenced by theological terminology.
Diabolology and diabology are essentially synonymous, but diabolology sounds more scholarly and formal—this shows how English sometimes creates multiple forms of the same word to suit different contexts!
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