Ar*ca"num (#), n.; pl. Arcana (#). [L., fr. arcanus closed, secret, fr. arca chest, box, fr. arcere to inclose. See Ark.]
1.
A secret; a mystery; -- generally used in the plural.
Inquiries into the arcana of the Godhead.
Warburton.
2. Med.
A secret remedy; an elixir.
Dunglison.
© Webster 1913.