noun

• (Greek mythology, Roman mythology) A mythological shield associated with the Greek deities Zeus and Athena (and their Roman counterparts Jupiter and Minerva) shown as a short cloak made of goatskin worn on the shoulders, more as an emblem of power and protection than a military shield. The aegis of Athena or Minerva is usually shown with a border of snakes and with the head of Medusa in the center.
  "The goat Amalthea, which had suckled Jove, being dead, that god is said to have covered his buckler with the skin thereof, whence the appellation Aegis, from αιξ, αιγις, a she-goat. Jupiter afterwards restoring the goat to life, covered it with a new skin, and placed it among the stars. This buckler, which was the work of Vulcan, he gave to Minerva, who having killed the Gorgon Medusa, nailed her head to the middle of the Aegis, which henceforth possessed the faculty of converting to stone all who beheld it, as Medusa herself had while alive."
• (figuratively) Usually as under the aegis: guidance, protection; endorsement, sponsorship.
  "[T]hree ex-Secretaries of State for War had learnt their military theory under the ægis of Regular soldiers. Now it is an admitted fact that, broad-minded and enterprising as soldiers have frequently proved themselves in matters unconnected with the actual corporate body to which they belong, they are, nevertheless, perhaps the most obstinate and optimistic advocates of a laissez-faire policy, which the interests of their own profession are at issue, that it is at all possible to conceive."

name

• (NASA) Acronym of Autonomous Exploration for Gathering Increased Science.