Where does “kupariruoste” come from?

kupariruoste (Finnish) comes from Finnish ruoste, from Proto-Finnic roostek, from Proto-Germanic rustaz, from Proto-Indo-European rudʰso-, from Proto-Indo-European h₁rewdʰ- — red.

Ancestry of “kupariruoste”, step by step

kupariruoste traces back through two separate lines of ancestry.

via Finnish ruoste

StepLanguageWordMeaning
1Finnishruosterust; rusty; inessive case is sometimes better...
2Proto-Finnicroostekrust
3Proto-Germanicrustazrust
4Proto-Indo-Europeanrudʰso-red
5Proto-Indo-Europeanh₁rewdʰ-red

via Finnish kupari

StepLanguageWordMeaning
1Finnishkuparicopper
2Old Swedishkoppar—
Every word from Proto-Indo-European h₁rewdʰ- →Every word from Proto-Indo-European rudʰso- →Every word from Proto-Germanic rustaz →