noun A period of seven days beginning with Sunday or Monday.
noun A period of five days beginning with Monday.
noun A subdivision of the month into longer periods of work days punctuated by shorter weekend periods of days for markets, rest, or religious observation such as a sabbath.
A 4-day week consists of Monday, Tuesday, Wednesday, and Thursday.
noun A date seven days after (sometimes before) the specified day.
I'll see you Thursday week. [a week on Thursday, i.e. Thursday after next]