Today this word is used by a conjuror in performing a trick, supposedly a charm that causes magic to work; or, more generally, it denotes meaningless talk and thus is used as a term of ridicule, but the word has a long history of use in ancient magical procedures. It was used as an amulet and often arranged in triangular form:
In this form, it was used as a charm to ward off disease. As the word diminishes when it is read downward, so, by sympathetic magic, the disease was supposed to diminish and finally end.
The first attested use of the term is in a second-century book Liber Medicinalis by Q. S. Sammonicus, who was a physician to the Roman Emperor Caracalla. The THEOSOPHICAL GLOSSARY states that abracadabra is a corruption of the Gnostic term ABRAXAS.
Philip Sydney Harris