Four groups of three days in the Church calendar during which fasting was observed, i.e. Wednesday, Friday and Saturday following the first Sunday in Lent, *Pentecost, Holy Cross Day (14 September), St Lucy's Day (13 December). Ember Week was one in which Ember days occurred. [< OldEngl. ymbren, ymbryne = course, anniversary]
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.