Definitions by The red willows com

Dianniversary 

The celebration of half an anniversary.

(not to be mistaken with bianniversary)

They got together on christmas, so their dianniversary would be june 25th.

Dianniversary by The red willows com June 17, 2009

Bianniversary 

The celebration of two years.

(not to be mistaken with dianniversary)

They got together on christmas 2005, so their bianniversary was on christmas 2007.

Bianniversary by The red willows com June 17, 2009