High Quality Content by WIKIPEDIA articles! A week is a time unit equal to seven days, originating in the calendar of the Jews in the 6th century BC and adopted in the Roman, Muslim and various other calendars. The English word week continues an Old English wice, ultimately from a Common Germanic wik n-, from a root wik- "turn, move, change". The Germanic word probably had a wider meaning prior to the adoption of the Roman calendar, perhaps "succession series", as suggested by Gothic wik translating taxis "order" in Luke 1:8. The term "week" is sometimes expanded to refer to other time units comprising a few days. Such "weeks" of between 4 and 10 days have been used historically in various places.