Where does “éra” come from?

éra (Czech) comes from Late Latin aera, from Latin aera, from Latin aes, from Proto-Italic aos, from Proto-Italic ajos, from Proto-Indo-European h₂éyos — a metal, copper, bronze.

éra (Czech): era, age

Definitions

era, age

Ancestry of “éra”, step by step

Step	Language	Word	Meaning
1	Late Latin	aera	era or epoch from which time is measured;...
2	Latin	aera	era or epoch from which time is measured;...
3	Latin	aes	money, pay, fee, fare; copper, bronze, brass;...
4	Proto-Italic	aos	bronze, copper
5	Proto-Italic	ajos	—
6	Proto-Indo-European	h₂éyos	a metal, copper, bronze

Every word from Proto-Indo-European h₂éyos →Every word from Proto-Italic ajos →Every word from Proto-Italic aos →