出典:Wiktionary
Origin obscure. Possibly from an earlier *scēadel, from Proto-West Germanic *skaidilu (“part in the hair, crown, summit”) ; if so, then cognate with Old Dutch skēthila, Old High German sceitila, skeitila. Otherwise, equivalent to sċēadan + -a. In any case, ultimately from Proto-Indo-European *skey- (“to cut, part, separate, divide”).