anniversary anniversary /ˌænɪˈvɜːrsəri/

noun

1. () The date on which an event occurred in some previous year (or the celebration of it)  ( day of remembrance , anniversary )
   the date on which an event occurred in some previous year (or the celebration of it)
    My grandparents celebrated their 50th wedding anniversary with a big party
   My grandparents celebrated their 50th wedding anniversary with a big party