one day of solar time, the time between successive noons; the time in which a planet such as Earth apparently rotates once around its axis, relative to the sun (on Earth about 24 hours as an average - the length of solar day is not constant throughout the year)
Any of the days of a week on which work is done. The five workdays in many countries are usually Monday to Friday (and are defined as such in official and legal usage even though many people work on weekends).
That part of a day in which work is done.