Esoteric. This term is from the Greek esōteros, meaning "inner" and is used, especially in contexts relating to Gnosticism, to designate a secret or hidden teaching that lies behind what is taught openly. The distinction between such esoteric teaching and its opposite (exoteric) has been made from antiquity in many, if not all the great religions. It is certainly to be found in much Indian thought. In some schools of Buddhism, too, there are stories of the Buddha's having taken apart certain disciples and conveyed to them a secret, hidden meaning behind his general teaching. Paul ( I Corinthians 2.6ff. and 3.1f.) specifically alludes to a hidden wisdom that only the spiritually perceptive can be expected to understand, not "carnal" people. The concept may be applied to Pythagoras and to the teachings of many of the great schools of Greek philosophy. In religion there is often a marked distinction between the way in which it is understood by the vast majority of the people and that in which the learned and spiritually-minded perceive and practice it. Taoism provides a striking example of the gulf between its popular and often very superstitious forms and the teaching of its reputed founder, Lao Tzu, which provides a deeply spiritual philosophy. Traditional Christianity also exhibits a marked distinction between what is formulated for the masses and what lies behind such teaching. (The Abbé Dimnet once defined the old papal index of books, the reading of which was prohibited to the people at large, as "a convenient device for enabling the learned to write without fear of offending pious ears.") The concept of esoteric teaching in religion is virtually universal.

Geddes MacGregor, Dictionary of Religion and Philosophy, New York: Paragon House, 1989

esoteric : (adj.) gūḷha; asabbasādhāraṇa.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]