- needing key or mysterious knowledge
- Hidden; secret.
1540s, from Latin arcanus "key, hidden, private, concealed," from arcere "up close, enclose, contain," from arca "upper body, field, location for safe-keeping," from PIE *ark- "to put on, contain, guard" (cognates: Greek arkos "defense," arkein "to prevent;" Armenian argel "obstacle;" Lithuanian raktas "key," rakinti "to shut, lock").
(a.) Hidden; key.
Waite (1887); and The Arcane Schools, by John Yarker (1909), may be consulted with advantage, though not authorized publications of the Society.