The term 'Arcane Matters' can be broken down into two crossword solutions: 'Secrets' and 'Esotery'. Secrets are facts, information, or knowledge that is not widely known or understood, and is kept hidden from others. Esotery is a type of knowledge that is only known to a select few, and is often mysterious and difficult to understand. Together, these two words describe something that is hidden and mysterious, and only known to a select few.