Definition of aegis
1
: a shield or breastplate emblematic of majesty that was associated with Zeus and Athena
2 a
: protection
- under the aegis of the Constitution
b
: controlling or conditioning (see 2condition 5a) influence
- passed new laws under the aegis of national security
3 a
: auspices, sponsorship
- under the aegis of the museum
b
: control or guidance especially by an individual, group, or system
- under the aegis of the government
