From Old Irish cerr (“crooked, maimed”), from Proto-Celtic *kersos (“maimed”), from Proto-Indo-European *(s)kersos, from a stem *(s)ker- (“to cut”). Cognates See also Lithuanian sker̃sas (“transverse, crooked”), Old Prussian kerscha, kērschan, kirsa, kirscha, kirschan (“over”), Proto-Slavic *čerzъ < *čersъ (Russian че́рез (čérez, “over, through; transverse, across, crosswise”), Bulgarian чрез (črez)), Ancient Greek ἐπικάρσιος (epikársios, “transverse, crosswise; lateral”).