Questions about example sentences with, and the definition and usage of "Aegis"

A: They operated under the imperial aegis.
(under the) aegis = with the protection, support of something.

The word comes from mythology, where it represents a shield associated with Zeus.

There is also a video game called Aegis Defenders.

A: "Protection" is a generic term. It means to defend or keep safe.

"Aegis" can mean "protection" but it often refers specifically to a type of shield or breastplate. We don't use the word "aegis" in regular conversation. Most people probably don't know this word at all. So don't worry about it.