A workplace myth popularized by Dolly Parton's theme song for the movie of the same name. It would seem to indicate one arrives at the office at 9am and leaves at 5pm. This somehow works out to an 8 hour day what with varying regulations about break time and lunch time and who pays for what.

I think this is pretty much a dead concept, at least for the time being. Knowledge workers putting in 18 hour days, telecommuting, and other recent trends in work arrangements have conspired to destabilize any notion of a uniform work schedule.