acroamatics
/ˌakrəʊəˈmatɪks/noun
Frequently with capital initial. (The name of) lectures given by Aristotle to intimate friends and scholars on the esoteric parts of his philosophy.
Origin
Mid 17th century. From acroamatic, after post-classical Latin acroamatica or its etymon Byzantine Greek τὰ ἀκροαματικά writings on esoteric subjects, use as noun of neuter plural of ἀκροαματικός.