[week] n [ME weke, fr. OE wicu, wucu; akin to OHG wehha week and perh. to L vicis change, alternation, OHG wehsal exchange] (bef. 12c) 1 a: any of a series of 7-day cycles used in various calendars; esp: a 7-day cycle beginning on Sunday and ending on Saturday b (1): a week beginning with a specified day or containing a specified holiday "the ~ of the 18th" "Easter ~" (2): a week appointed for public recognition of some cause "Fire Prevention Week"
2. a: any seven consecutive days b: a series of regular working, business, or school days during each 7-day period
3: a time seven days before or after a specified day "last Sunday ~"