n., pl., -na (-nə), or -nums.
- A deep secret; a mystery.
- often arcana Specialized knowledge or detail that is mysterious to the average person: "knows the arcana of police procedure and the intricacies of litigation" (George F. Will).
- A secret essence or remedy; an elixir.
[Latin arcānum, from neuter of arcānus, secret. See arcane.]




