Any period of seven consecutive days.
A period of seven days beginning with Sunday or Monday.
A period of five days beginning with Monday.
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.
Seven days after (sometimes before) a specified date.
I'll see you Thursday week.