Hesychasm (Greek: ἡσυχασμός, contemporary Byzantine Greek pronunciation: [isixaˈzmos], from ἡσυχία Greek pronunciation: [isiˈçia], esychía, "stillness, rest, quiet, silence") is a mystical tradition of prayer in the Eastern Orthodox Church (Gk: ἡσυχάζω Greek pronunciation: [isiˈxazo]: "to keep stillness") by the Hesychast (Gr. Ἡσυχαστής Greek pronunciation: [isixaˈstis]).
Based on Christ's injunction in the Gospel of Matthew that "when thou prayest, enter into thy closet, and when thou hast shut thy door, pray", hesychasm in tradition has been the process of retiring inward by ceasing to register the senses, in order to achieve an experiential knowledge of God (see theoria).
Metropolitan Kallistos Ware, a distinguished scholar of Orthodox theology, distinguishes five distinct meanings of the term "hesychasm":
The origin of the term hesychasmos, and of the related terms hesychastes, hesychia and hesychazo, is not entirely certain. According to the entries in Lampe's A Patristic Greek Lexicon, the basic terms hesychia and hesychazo appear as early as the 4th century in such fathers as St John Chrysostom and the Cappadocians. The terms also appear in the same period in Evagrius Pontikos (c. 345 – 399), who although he is writing in Egypt is out of the circle of the Cappadocians, and in the Sayings of the Desert Fathers.