The hours and days when businesses generally operate; 8:00 AM to 5:00 PM, Monday to Friday.
The hours and days when a given business is available to the public.
Any of those days of a week on which work is done, officially Monday to Friday in many countries (even though many people work on weekends).
The part of a day in which work is done; the number of hours one must work per day for a specified wage.