Where does “birna” come from?

birna (Kashubian) comes from German Birne, from Middle High German bire, from Old High German bira, from Vulgar Latin pira, from Latin pirum — a pear.

Ancestry of “birna”, step by step

StepLanguageWordMeaning
1GermanBirnepear; lightbulb; head, bonce, noggin
2Middle High Germanbire—
3Old High Germanbirapear
4Vulgar Latinpira—
5Latinpiruma pear
Every word from Latin pirum →Every word from Vulgar Latin pira →Every word from Old High German bira →