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Anniversary from WikiPedia:

An anniversary (from the Latin anniversarius, from the words for year and to turn, meaning (re)turning yearly; known in English since c. 1230) is a day that commemorates and/or celebrates a past event that occurred on the same day of the year as the initial event. For example, the first event is the initial occurrence or, if planned, the inaugural of the event. One year later would be the first anniversary of that event. The word was first used for Catholic feasts to commemorate saints.

For monthly recurrences, one might say mensiversary, from the Latin word mensis, for month, and versus, meaning to (re)turn. Mensiversary was used in a 1925 Time magazine article, titled 18th Mensiversary.

• Birthdays (v.) are the most common type of anniversary, where the birth date of a person is commemorated annually. The actual celebration is sometimes moved for practical reasons, as in the case of an official birthday.
• Wedding anniversaries are also often celebrated on the same day of the year as the wedding occurred.
• Death anniversary.

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