Uncertain; proposed derivations include:
* From a root common to Ancient Greek σκίδνημι (skídnēmi, “to disperse”) and Lithuanian kedeti (“to burst”).
* From Proto-Indo-European *(s)ker- (“to cut”). Cognates include cortex (“bark”) and Ancient Greek κείρω (keírō, “to cut off”).
* From Proto-Indo-European *ḱes- (“to cut”), with the possible cognate careō (“I lack”).