had ter look this one up and still puzzledEsoteric knowledge, in the dictionary (non-scholarly) sense, is thus that which is available only to a narrow circle of "enlightened", "initiated", or specially educated people.[2] Esoteric items may be known as esoterica.[3] In contrast, exoteric knowledge is knowledge that is well-known or public; or perceived as informally canonic in society at large.
In Western, English-speaking societies today, the term "esotericism" is not necessarily used in the sense of mystical knowledge or practice, but rather informally to mean any perception or knowledge that is difficult to understand or remember, such as theoretical physics, or that pertains to the minutiae of a particular discipline, such as "esoteric" baseball statistics.