'arcana' originates from Latin, specifically the word 'arcanum', where 'arcanus' meant 'secret' or 'hidden'.

'arcana' changed from the Latin/Medieval Latin word 'arcanum' and entered English usage (via Medieval Latin) to refer to secrets or hidden things; the plural form 'arcana' has been adopted in English as a collective noun.

Initially, it meant 'a secret or hidden thing' in Latin; over time it evolved into its current usage referring to 'secrets, mysteries, or esoteric knowledge' and specialized senses such as tarot 'arcana'.