Similar to anniversary, but occuring every month. For people who are overzealous about a new relationship.
Cara and Sloopy's monthiversary is January 5, 2008.
by Cara and Sloopy October 20, 2005
A celebration every consecutive month that you have been in a relationship with your boyfriend/girlfriend.

A.K.A:

An excuse to buy her a present.

Something that she might bitch at you for forgetting.

A good day to pig out on cake and/or make out.

If you're in high school, a motive to skip homework and go play lazer tag.

Another walk of life celebrated by a useless holiday.

A contest to see how many months more you can stand one another than another couple.

Just another way to express undying love, or some similar feeling of mindless infatuation.
"Ted, where the HELL IS MY MONTHIVERSARY PRESENT, you cheap bastard??"
by memyselfandpickles May 17, 2010
Noun. The day on the proceding month of being in a relationship. Ani=Year, Month=Month therefore im stupid and came up with this word.
by ian mcquay?? November 26, 2004
a date when a couple met each other for the first time and they celebrate on that exact date every month
Hey babe! Today is the 13th. It's our monthiversary.
yeah, happy monthiversary!
by Matti September 17, 2018
Monthly renewal or premium date, comes from the insurance business -- anniversary wasn't often enough.
Is that policy up to date?
Check to see if they renewed by the monthiversary.
by the original craigo January 2, 2008
When you celebrate being with your significant other every month. But before completing a year together, it would just be a monthiversary.
When you celebrate your 1st Anniversary on the 15th of June, July 15th would be your 13th Anni-Monthiversary because it's 12 months + 1 month.
by Ranshan Gomez October 16, 2009