An enchantress is usually defined as a magician, sorcerer, enchanter or wizard.I think "Empress" is a typo for "Enchantress."
For author Maggie Anton, an enchantress is also a sorceress or a woman who practices magic. Anton explains on her blog that when she was preparing to write “Enchantress,” (the sequel to “Rav Hisda’s Daughter”), she and a rabbi colleague went through “the entire Talmud again, tractate by tractate, searching for every mention of demons, magic, and enchantresses. We found far more than I expected; some stories were quite fantastic.”
“Empress” features Hisdadukh, the daughter of Rav Hisda, and is set in Babylonia from 299 C.E. to 359 C.E.
More on Anton, this latest book, and her earlier novels is here and links.