- a secret, typically one understood by or revealed to only a few; mystery: usually used in pl.
- Archaic a secret remedy; elixir
Origin of arcanumL, neuter of arcanus, shut in, hidden ; from arcere, to enclose: see exercise
nounpl. ar·ca·na or ar·ca·nums
- A deep secret; a mystery.
- 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).
- A secret essence or remedy; an elixir.
Origin of arcanumLatin arcanum, from neuter of arcanus, secret; see arcane.