Agnesi, Maria Gaetana Syllabification: (Agne·si, Maria Gaetana)Pronunciation: /änˈyāzē/Definition of Agnesi, Maria Gaetana (1718–99), Italian mathematician and philosopher. She wrote a mathematics textbook and was the first woman appointed to a university chair in mathematics. Agnesi, Maria Gaetana in other Oxford dictionaries Definition of Agnesi, Maria Gaetana in the British & World English dictionary