Arcanum
Pronunciation : Ar*ca"num
Part of Speech : n.; pl. Arcana.
Etymology : [L., fr. arcanus closed, secret, fr. arca chest, box, fr. arcere to inclose. See Ark.]
Definition : 1. A secret; a mystery; -- generally used in the plural. Inquiries into the arcana of the Godhead. Warburton.
2. (Med.)
Defn: A secret remedy; an elixir. Dunglison.
Source : Webster's Unabridged Dictionary, 1913