Latin for 'year-turning' — the point at which the calendar has come full circle to a significant date.
The date on which an event took place in a previous year; the annual celebration or commemoration of such a date.
From Latin 'anniversārius' (returning yearly), from 'annus' (year) + 'versus,' past participle of 'vertere' (to turn), from PIE *wer- (to turn, to bend). An anniversary is literally a 'year-turning' — the point at which the year has turned full circle back to a significant date. Key roots: annus (Latin: "year"), versus (Latin: "turned (past participle of vertere)"), *wer- (Proto-Indo-European: "to turn, to bend").
In medieval English, 'anniversary' almost always referred to the yearly commemoration of someone's death — a requiem Mass held on the annual return of the date. The cheerful modern association with weddings and birthdays is a relatively recent development. The medieval Church calendar was structured around death anniversaries, and the word carried