arcaneyoudaoicibaDictYouDict
arcane: [16] Arcane comes from the Latin adjective arcānus ‘hidden, secret’. This was formed from the verb arcēre ‘close up’, which in turn came from arca ‘chest, box’ (source of English ark). The neuter form of the adjective, arcānum, was used to form a noun, usually used in the plural, arcāna ‘mysterious secrets’.
=> ark
arcane (adj.)youdaoicibaDictYouDict
1540s, from Latin arcanus "secret, hidden, private, concealed," from arcere "close up, enclose, contain," from arca "chest, box, place for safe-keeping," from PIE *ark- "to hold, contain, guard" (cognates: Greek arkos "defense," arkein "to ward off;" Armenian argel "obstacle;" Lithuanian raktas "key," rakinti "to shut, lock").