"Aegis" (pronounced /ˈiːdʒɨs/) has entered modern English to mean a shield, protection, or sponsorship, originally from the name of the mythological protective shield of Zeus. The name has been extended to many other entities, and the concept of a protective shield is found in other mythologies, while its form varies across sources.
The concept of doing something "under someone's aegis" means doing something under protection of a powerful, knowledgeable, or benevolent source. The word aegis is identified with protection by a strong force with its roots in Greek mythology, adopted by the Romans; there are parallels in Norse mythology, and in Egyptian mythology as well, where the Greek word aegis is applied by extension.
