Arcana' refers to hidden or SECRET knowledge. It is a term used in occult studies and esoteric traditions to refer to the hidden wisdom that is understood only by a select few. The word comes from the Latin word arcanus, which means 'SECRET' or 'MYSTERIOUS'. OBSCURE MATTERS (7 letters) 'Obscure Matters' refers to topics that are not widely known or understood. These topics may be difficult to grasp or require specialized knowledge in order to fully comprehend them. They are often considered too complex or esoteric for the general public to fully understand.