Where does “надвое” come from?

надвое (Russian) comes from Russian на́, from Proto-Slavic na, from Proto-Indo-European h₂en- — on, onto.

надвое (Russian): in two, in half, into two parts; ambiguously,...

Definitions

  1. in two, in half, into two parts; ambiguously,...

Ancestry of “надвое”, step by step

надвое traces back through 3 separate lines of ancestry.

via Russian на́

StepLanguageWordMeaning
1Russianна́here you go! (encouraging someone to accept something, used when giving or providing something, i.e., "take it!", "here you goǃ")
2Proto-Slavicnaon; concerning; onto
3Proto-Indo-Europeanh₂en-on, onto

via Russian дво́е

StepLanguageWordMeaning
1Russianдво́еtwo
2Proto-Slavic*dъvojьtwo

via Belarusian двое

StepLanguageWordMeaning
1Belarusianдвоеtwo; two of.
Every word from Proto-Indo-European h₂en- →Every word from Proto-Slavic na →Every word from Russian на́ →