Where does “fronces” come from?

fronces (Old French) comes from Frankish hrunkja, from Proto-Germanic hrunkijō, from Proto-Indo-European sḱer- — to caw, crow.

Ancestry of “fronces”, step by step

StepLanguageWordMeaning
1Frankishhrunkjawrinkle; a wrinkle
2Proto-Germanichrunkijō—
3Proto-Indo-Europeansḱer-to caw, crow
Every word from Proto-Indo-European sḱer- →Every word from Proto-Germanic hrunkijō →Every word from Frankish hrunkja →