esoteric

Esoteric originally described what belonged to an inner circle: in Ancient Greek, ἐσωτερικός (esōterikós) meant “belonging to an inner circle.” The Greek word came through ἐσωτέρω (esōtérō), “further inside,” comparative of ἔσω (ésō), “within,” itself traced to ἐς (es) and εἰς (eis), “into.” English borrowed it as a learned word for teachings meant for a select group, contrasted with public or “exoteric” teachings. It now commonly describes knowledge understood by only a few specialists, and can also mean highly theoretical, mystical, confidential, or private. Lucy S. Dawidowicz used “esoteric language” in 1975 for language that insiders could interpret beneath an innocuous public reading; Saul Bellow’s 1976 novel Humboldt’s Gift uses the phrase “esoteric mysteries.”