A digital watch is one where the time is displayed numerically without hands. We might term “pure digital” those in which the relevant numbers appear in an aperture either by jumping or continuous movement. Although technically more demanding, jumping numbers – where a small spring is primed within the mechanism to change the digit instantaneously – give a much more pleasing display. Continuous progression means that the numbers are rarely aligned with the aperture or pointer and can make the display look very untidy.
“Wandering hours” watches usually indicate the hour via digits in an aperture, while the minutes are shown through the movement of the aperture either around the outside of the dial or across a calibrated scale. It could be argued that this is not a true digital as the hour digit ostensibly acts as a hand but the main presentation of the time is numerical and they do differ dramatically from the conventional analogue display.