noun (n)

• any period of seven consecutive days(noun.time)

  Example:
  It rained for a week.
  

  Synonym:
  hebdomad
  

  source: wordnet30
• hours or days of work in a calendar week(noun.time)

  Example:
  They worked a 40-hour week.
  

  Synonym:
  workweek
  

  source: wordnet30
• a period of seven consecutive days starting on Sunday(noun.time)

  Synonym:
  calendar week
  

  source: wordnet30
• A period of seven days, usually that reckoned from one Sabbath or Sunday to the next.(noun)

  source: webster1913