phylactery (n.)

late 14c., "small leathern box containing four Old Testament texts," from Old French filatiere (12c.) and directly from Medieval Latin philaterium, from Late Latin phylacterium "reliquary," from Greek phylacterion "safeguard, amulet," noun use of neuter of adjective phylakterios "serving as a protection," from phylakter "watcher, guard," from phylassein "to guard or ward off," from phylax (genitive phylakos) "guardian, watcher, protector," a word of unknown origin; Beekes writes that, based on the suffix -ax, "the word may well be pre-Greek." Sometimes worn on the forehead, based on a literal reading of scripture:

Ye shall bind them [i.e. my words] for a sign upon your hands, and they shall be for frontlets between your eyes. [Deuteronomy xi.18]

Others Are Reading