A day subsequent in time to a given event by some significant period other than a year (especially as prefixed by the amount of time in question).
A day that is an exact number of years (to the day) since a given significant event occurred. Often preceded by an ordinal number indicating the number of years.
Such a day that commemorates a wedding.
The date by which a task is supposed to be completed.
The date on which a pregnant woman is expected to give birth.
The date by which a book (or other item) borrowed from a library must be returned.
The date of payment in financial arrangements.