1. Recurring at a slated time; yearly.

2. The day of the year on which a remarkable event happened its annual celebration.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• anniversarry,
• aniversay,
• anniversey,
• anniversiary,
• anneversary,
• annivrsary,
• aniversery,
• aniverssary,
• annoversary,
• aniversry,
• anniversity,
• anniverasry,
• annaversery,
• aniversairy,
• annaversay,
• annerversary,
• annversary,
• anniversry,
• anniveriary,
• anniversarys

The adjective form of the word "anniversary" is "anniversary" itself. For example, "We celebrated our tenth anniversary".

The plural of the "anniversary" can be the "anniversaries".

The singular of the "anniversary" can be the "anniversary".