egis vs breastplate

egis and breastplate both are nouns.

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

As nouns, egis and breastplate are synonyms defined as:

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

Other synonyms of egis include aegis.

egis (noun)	breastplate (noun)
armor plate that protects the chest; the front part of a cuirass	armor plate that protects the chest; the front part of a cuirass