ABRACADABRA, is an ancient word of Middle Eastern origin, believed for many centuries to have the magical power to ward off evil spirits, misfortune, or disease. By one account, the word was derived from Abrazas, which was a magical word used by the Basilidian Gnostics, a religious sect originating in the 2d century. By another account, the term was composed of the first letters of the Hebrew words for Father, Son, and Holy Spirit (Ab, Ben, Ruach, Acadosh).
The first recorded mention of abracadabra is in Q. Sereni liber, a work on remedies against disease, written in the 2d, 3d, or 4th century. The author (identity uncertain) prescribes that the word be written on paper in successive centered lines, each line omitting the last letter of the line above until the repetitions form an inverted triangle with its apex the letter A. The paper is then folded, worn on linen as an amulet for nine days, and before sunrise thrown backward into a stream flowing east.
In modern times, the word is commonly uttered by performers of sleight-of-hand tricks.