A day display shows the current day of the week, typically in association with a date or more complex calendar complication.
A day display is one of the simplest complications to implement, since unlike the date there are no skipped days. Many watches feature both day and date, but none is known to feature only the day.
The day display typically uses a simple wheel mechanism with each day written on a disc and viewed through an aperture in the dial. The day is sometimes written out but is often abbreviated with three capital letters. Some day wheels feature two or more languages alternating on the disc, skipping one with each turn, allowing a multilingual display. The day aperture is traditionally placed next to the date at 3 00 on the dial using co-axial discs.
The day can also be displayed by pointer, with a hand indicating the current date using printing on the dial.