A four-day workweek.
A forty-hour workweek.
You'd say things like, " Wow, that workweek really flew bye.
The 40 hour workweek has become, during the past twenty years, the 60 hour work week.
Some companies only require a 30-hour workweek.
Go back to work, but for the first month or two, cut your workweek by one day.
You may want to consider this bag for your nine-to-five workweek.