What is the origin and context of use of 'abracadabra'?

The origins of "abracadabra" trace back to ancient times, particularly to the Roman era. It's believed to have been used as a magical incantation or charm, believed to possess protective or healing properties. The exact origin and meaning are uncertain, but it was often associated with amulets worn to ward off illnesses or evil spirits. In modern times, "abracadabra" is mostly known as a theatrical expression used by magicians to accompany their sleight of hand or illusions. It's often said with a flourish or dramatic gesture to create an air of mystery and wonder during magic performances.