Demiversary 

A demiversary is a "six month anniversary".

The term "six month anniversary" annoyed me enough to create the word "demiversary".
Joe and Jane Doe are having their demiversary.

Demiversary by comradeda August 28, 2011

semiversary 

6 month aniversary.

A shortened version of the word semianniversary.

On the inside of a card:
Happy semiversary

semiversary by KoH March 20, 2007

dumpiversary 

a year later after you stopped seeing someone, you think everyone is getting on with their lives and then the crazy person you let go starts making trouble for you because it was this time last year they suddenly found out the world didn't revolve around them.

it must be my dumpiversary because my ex has gone through his phonebook telling tales outta school to people.

dumpiversary by gettingonwithlife July 11, 2010

demiversaire

The date which is equally distance between ones birthday.

I can't believe you forgot my demiversaire!

demiversaire by EvilleRabbits April 29, 2021

dadiversary 

The anniversary of the day you became a dad. Usually on the birthday of your oldest child.

Hey man I hear your kid just turned 10, Happy Dadiversary!

dadiversary by ditzydory November 26, 2016