anniversary
n. countablen. the date on which an important event happened in a previous year. You usually celebrate this day to remember a wedding, a business opening, or a historical event.
n. the annual recurrence of a date marking a notable past event. Often used with ordinal numbers to indicate the duration of time since the original occurrence.
They are celebrating their tenth wedding anniversary today.
The company held a gala dinner to mark the fiftieth anniversary of its founding.
While many view the anniversary as a time for celebration, for others it serves as a somber reminder of the historical tragedy that occurred on that same date decades ago.
From Middle English anniversary, from Medieval Latin anniversāria (diēs), anniversārium, from anniversārius (“yearly”), from annus (“year”) + versus, past participle of vertere (“to turn”).
Commonly takes the preposition 'of' followed by the event being remembered.
They celebrated their anniversary of marriageThey celebrated their wedding anniversaryIn English, 'wedding anniversary' is the standard compound noun; using 'anniversary of marriage' sounds unnatural to native speakers.