For a long time the regulator has been a reference device used to set the time on watches. Usually a high quality clock that is used to reference the time. However currently a regulator refers to a watch that has hands that are offset and do not rotate around the same axis. Separate time registers.
The minute hand rotates from the centre of the dial however the hours and seconds are indicated via separate dials of different sizes for example the main hand indicating the hours, the minutes dial being at the top and the seconds at the bottom.