Where does “остроугольный” come from?

остроугольный (Russian) comes from Russian о́стрый, from Proto-Slavic ostrъ, from Proto-Balto-Slavic aśras, from Proto-Indo-European *h₂eḱrós, from Proto-Indo-European h₂eḱ- — sharp.

остроугольный (Russian): acute-angled

Definitions

  1. acute-angled

Ancestry of “остроугольный”, step by step

остроугольный traces back through two separate lines of ancestry.

via Russian о́стрый

StepLanguageWordMeaning
1Russianо́стрыйpointed, sharp; sharp, pointed
2Proto-Slavicostrъsharp
3Proto-Balto-Slavicaśrassharp
4Proto-Indo-European*h₂eḱróssharp
5Proto-Indo-Europeanh₂eḱ-sharp

via Russian у́гол

StepLanguageWordMeaning
1Russianу́голangle; corner
2Proto-Slavicǫgъlъcorner, angle
3Proto-Balto-Slavic*ángulas—
4Proto-Indo-Europeanh₂engulosjoint?
5Proto-Indo-Europeanh₂eng-curve, bend
Every word from Proto-Indo-European h₂eḱ- →Every word from Proto-Indo-European *h₂eḱrós →Every word from Proto-Balto-Slavic aśras →