say it: an-uh-VUR-sur-ee
anniversary is a noun meaning "the date on which an event occurred in some previous year (or the celebration of it)". It is pronounced /ˌænəˈvɝsɚi/ — an-uh-VUR-sur-ee. It carries one recorded sense.
the date on which an event occurred in some previous year (or the celebration of it)
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for anniversary come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.