aegis vs breastplate

aegis and breastplate both are nouns.

Word	Noun	Adjective	Verb	Adverb
aegis	Yes	No	No	No
breastplate	Yes	No	No	No

As nouns, aegis and breastplate are synonyms defined as:

aegis and breastplate: armor plate that protects the chest; the front part of a cuirass

Other synonyms of aegis include egis.

aegis (noun)	breastplate (noun)
kindly endorsement and guidance	armor plate that protects the chest; the front part of a cuirass
armor plate that protects the chest; the front part of a cuirass