Where does “твердыня” come from?

твердыня (Russian) comes from Russian твёрдый, from Old East Slavic твьрдъ, from Proto-Slavic tvьrdъ, from Proto-Balto-Slavic *twírˀtas, from Proto-Indo-European twerH- — to enclose, fence in; to grab, seize; to stir.

твердыня (Russian): stronghold also figuratively

Definitions

  1. stronghold also figuratively

Ancestry of “твердыня”, step by step

StepLanguageWordMeaning
1Russianтвёрдыйhard, solid; firm; steadfast, steady
2Old East Slavicтвьрдъ—
3Proto-Slavictvьrdъhard, firm, solid
4Proto-Balto-Slavic*twírˀtashard, firm, solid
5Proto-Indo-EuropeantwerH-to enclose, fence in; to grab, seize; to stir
Every word from Proto-Indo-European twerH- →Every word from Proto-Balto-Slavic *twírˀtas →Every word from Proto-Slavic tvьrdъ →