n. pl. ar·ca·na (-nə) or ar·ca·nums
1. A deep secret; a mystery.
2. often arcana Specialized knowledge or details unknown to or misunderstood by the average person: "a private-equity investor whose specialty was the arcana of the banking industry" (Andrew Ross Sorkin).
3. A secret essence or remedy; an elixir.
[Latin arcānum, from neuter of arcānus, secret; see ARCANE.]
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