Definition of anniversaries:
(n) :
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.
(n) :
(especially) Such a day that commemorates a wedding.
(n) :
(loosely) 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).