Meaning

noun a sedimentary rock formed by the deposition of successive layers of clay

originFrom Middle English schale (“shell, husk; scale”), from Old English sċealu (“shell, husk, pod”), from Proto-West Germanic *skalu, from Proto-Germanic *skalō, from Proto-Indo-European *(s)kelH- (“to split, cut”), from *(s)kel- (“to split, cleave”). See also West Frisian skaal (“dish”), Dutch schaal (“shell”), schalie (“shale”), German Schale (“husk, pod”); also Lithuanian skalà (“splinter”), Old…

Etymology from Wiktionary, CC BY-SA 3.0