What is "fadilla"

Annia Aurelia Fadilla, most commonly known as Fadilla (159-died after 211) was an influential Roman Princess and was one of the daughters born to Roman Emperor Marcus Aurelius and Roman Empress Faustina the Younger. She was a sister to Roman Empress Lucilla and Roman Emperor Commodus. Fadilla was named in honor of her late maternal aunt Aurelia Fadilla. The cognomen Fadilla, was the cognomen of the mother and a half-sister of the previous Roman Emperor Antoninus Pius. Her maternal grandparents were Roman Emperor Antoninus Pius and Roman Empress Faustina the Elder and her paternal grandparents were Domitia Lucilla and praetor Marcus Annius Verus.