Word Origin & History
arcane1540s, from L. arcanus "secret, hidden," from arcere "close up, enclose, contain," from arca "chest, box," from PIE *ark- "to hold, contain, guard" (cf. Gk. arkos "defense," arkein "to ward off;" Arm. argel "obstacle;" Lith. raktas "key," rakinti "to shut, lock").