n.1 (in full sabbath day) a day of rest and religious observance kept by Christians on Sunday, Jews on Saturday, and Muslims on Friday.
2 a period of rest.
3 (in full witches' sabbath) a supposed general midnight meeting of witches with the Devil.
Etymology: OE sabat, L sabbatum, & OF sabbat, f. Gk sabbaton f. Heb. sabbat f. sabat to rest