Where does “rozostřit” come from?

rozostřit (Czech) comes from Czech ostřit, from Czech ostrý, from Proto-Slavic ostrъ, from Proto-Balto-Slavic aśras, from Proto-Indo-European *h₂eḱrós, from Proto-Indo-European h₂eḱ- — sharp.

Ancestry of “rozostřit”, step by step

StepLanguageWordMeaning
1Czechostřitto sharpen
2Czechostrýsharp; hot; strict
3Proto-Slavicostrъsharp
4Proto-Balto-Slavicaśrassharp
5Proto-Indo-European*h₂eḱróssharp
6Proto-Indo-Europeanh₂eḱ-sharp
Every word from Proto-Indo-European h₂eḱ- →Every word from Proto-Indo-European *h₂eḱrós →Every word from Proto-Balto-Slavic aśras →