an·ni·ver·sa·ry (ān'ə-vûr'sə-rē) n.
pl.an·ni·ver·sa·ries
The annually recurring date of a past event, especially one of historical, national, or personal importance: a wedding anniversary; the anniversary of the founding of Rome.
A celebration commemorating such a date.
[Middle English anniversarie, from Medieval Latin (diēs) anniversāria, anniversary (day), from Latin, feminine of anniversārius, returning yearly : annus, year; see at- in Indo-European roots + versus, past participle of vertere, to turn; see wer-2 in Indo-European roots.]
[an-uh-vur-suh-ree] 
noun, plural -ries, adjective 