any of the days in the quarterly three-day period of prayer and fasting (the Wednesday, Friday, and Saturday after the first Sunday in Lent, after Whitsunday, after Sept. 14, and after Dec. 13) observed in the Roman Catholic Church and other Western churches.
The Origin Of Dog DaysThe exact dates of the dog days depend on your latitude, but by today’s estimation they begin on July 3 and come to a close on August 11.
Origin of Ember day
before 1050; Middle English ymber day, Old English ymbrendæg, plural -dagas, equivalent to ymbryne recurrence (ymb(e) around + ryne a running) + dæg day
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British Dictionary definitions for ember days
RC Church Anglican Church any of four groups of three days (always Wednesday, Friday, and Saturday) of prayer and fasting, the groups occurring after Pentecost, after the first Sunday of Lent, after the feast of St Lucy (Dec 13), and after the feast of the Holy Cross (Sept 14)
Word Origin for Ember days
Old English ymbrendǣg, from ymbren, perhaps from ymbryne a (recurring) period, from ymb around + ryne a course + dǣg day
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012