From wikipedia: The word “Abracadabra” may derive from an Aramaic phrase meaning “I create as I speak.” This etymology is rather dubious, however, as אברא כדברא in Aramaic is more reasonably translated "I create like the word." In the Hebrew language, the phrase translates more accurately as "it came to pass as it was spoken."
Interesting since Aramaic was the original language that the Bible was written in and the language of the people in the Bible for the most part. I never knew this. Pretty neat and JK Rowling.. you sly dog you. Slipping that one in there.
ARAMAIC The Aramaic language was the international trade language of the ancient Middle East between 1000 and 600 BCE, spoken from the Mediterranean coast to the borders of India. Its script, derived from Phoenician and first attested during the 9th century BCE, also became extremely popular and was adopted by many people with or without any previous writing system