In terms of formal definition, "Esoterism" signifies the holding of esoteric opinions or beliefs,[1] that is, ideas preserved or understood by a small group or those specially initiated, or of rare or unusual interest.[2] The term derives from the Greek ἐσωτερικός (esôterikos), a compound of ἔσω (esô): "within", thus "pertaining to the more inward", mystic. Its antonym is "exoteric".
From a scholastic perspective, the term designates a series of historically related religious currents including Astrology, Alchemy, Christian mysticism of Meister Eckhart, Johannes Tauler, and Henry Suso, the Christian Theosophy of Jacob Böhme and his followers, Illuminism, Mesmerism, Magic, Rosicrucianism, Swedenborgianism, Spiritualism, the theosophical currents associated with Helena Blavatsky and her followers, and Rudolf Steiner. There are competing views regarding the common traits uniting these currents, not all of which involve "inwardness", mystery, occultism or secrecy as a crucial trait.