noun, plural ar·ca·na /ɑrˈkeɪ
nə/ Show Spelled [ahr-key-nuh] Show IPA . 1.Often, arcana. a secret; mystery.
2.a supposed great secret of
nature that the alchemists sought to discover.
Origin: 1590–1600; <
Latin, neuter (used as noun) of
arcānus arcane