Where does “Orel” come from?

Orel (Portuguese) comes from Russian Орёл, from Old East Slavic орьлъ, from Proto-Slavic orьlъ, from Proto-Balto-Slavic *arélis, from Proto-Indo-European h₃érō — eagle.

Ancestry of “Orel”, step by step

StepLanguageWordMeaning
1RussianОрёлAquila (constellation)
2Old East Slavicорьлъ—
3Proto-Slavicorьlъeagle
4Proto-Balto-Slavic*aréliseagle
5Proto-Indo-Europeanh₃érōeagle
Every word from Proto-Indo-European h₃érō →Every word from Proto-Balto-Slavic *arélis →Every word from Proto-Slavic orьlъ →