An anniversary is a day that marks a special event, such as a wedding or the founding of a company. There are many synonyms for the word anniversary, which can be used to add variety and richness to your writing. Some possible synonyms include celebration, commemoration, remembrance, observance, jubilee, milestone, and landmark. Each of these words connotes a slightly different nuance or emphasis, so choose the one that best fits the tone and context of your writing. Whether you're writing a love letter to your spouse or a corporate memo to your colleagues, using a synonym for anniversary can help to keep your prose fresh and engaging.