noun
anniversary
an-ih-VUR-suh-ree/ˌænɪˈvɜːrsəri/
The yearly return or commemoration of the date of a past event.
The couple celebrates their wedding anniversary with a quiet dinner.

Etymology
The image is of a year turning back to the same date. The word originally referred especially to the yearly remembrance of a death or a saint’s martyrdom.
In context
this past Veterans Day, I went to Seoul and joined our Korean War veterans for the 60th anniversary of that war
More examples
- The museum marks the hundredth anniversary of its opening.
- She returns each year on the anniversary of the rescue.
- Important anniversaries appear on the family's kitchen calendar.
Forms
anniversary · anniversaries
Similar words
- commemoration
- Can occur without being tied to the yearly return of a date.
- birthday
- Specifically commemorates a person's birth or an institution's founding.