From Middle High German runzel, from Old High German runzula, runzila, a diminutive of Proto-West Germanic *hrunkitā (“wrinkle”), from Proto-Indo-European *(s)kreng-, from a nasalized form of Proto-Indo-European *(s)kerg-, from a phonetic extension of Proto-Indo-European *(s)ker- (“to turn, bend”). Compare Swedish rynka (“wrinkle”).