English word era comes from Proto-Indo-European *h₂éyos (A metal, copper, bronze.), Proto-Indo-European *áyos
| Dictionary entry | Language | Definition |
|---|---|---|
| *h₂éyos | Proto-Indo-European (ine-pro) | A metal, copper, bronze. |
| *áyos | Proto-Indo-European (ine-pro) | |
| *aos | Proto-Italic (itc-pro) | Bronze, copper. |
| aes | Latin (lat) | Copper, bronze, brass. Money, pay, fee, fare. Payment, debt. |
| aera | Late Latin (LL) | |
| era | English (eng) | (geology) A unit of time, smaller than eons and greater than periods.. A time period of indeterminate length, generally more than one year. |