Monthsary, Monthiversary or Mensiversary? The Right Word for a Monthly Anniversary

It usually starts with a caption. You are about to post a photo for your one-month mark and the keyboard freezes under your thumbs: is it monthsary or monthversary? Monthiversary? Is monthsaries even correct, or did your friends make that up? You type one, delete it, type the other, and finally search — which is probably how you landed here.

Good news: you are not confused, the language genuinely is. English never had an official word for a monthly anniversary, so lovers around the world invented several. Here is what each one means, where it came from, and which one you can use without a single grammar guilt pang.

Monthsary is the champion of the Philippines and much of South and Southeast Asia, including India. It is a simple, cheerful blend of month + anniversary, and it is by far the most-used word for celebrating each month of a relationship. If your feed is full of happy monthsary posts, this is your region's word.

Monthiversary (sometimes spelled monthversary, without the i) is the version you will hear more in the US and UK. Same blend, slightly different glue. Neither spelling is more official than the other — dictionaries list both as informal coinages — so pick the one that sounds right to your ears and stay consistent.

Mensiversary is the Latin nerd of the family: mensis (month) + versus (turning), built exactly the way anniversary was built from annus (year). It appears in a few older dictionaries and legal-ish writing, which makes it technically the most etymologically correct option — and also the one guaranteed to make your partner say what did you just call me?

As a plural, yes — monthsaries is simply more than one monthsary, the same way anniversaries is the plural of anniversary. Happy 5 monthsaries to us is grammatically fine as informal English; most couples would phrase it happy 5th monthsary, using the ordinal for the milestone itself.

The bigger point: none of these words appear in formal style guides, and none of them need to. They are affection words, not exam words. Monthsary is correct the way cuddle is correct — because millions of people use it and everyone understands exactly what it means.

Purists will tell you an anniversary can only be yearly, because annus literally means year — and on the etymology, they are right. But celebrations are not ruled by Latin. Monthly milestones exist because early relationships move fast: the difference between month two and month five can feel bigger than the difference between year two and year five. Marking months is how new couples make the growing visible.

That is also why monthsaries naturally fade as relationships mature — around the one-year mark most couples graduate to yearly anniversaries, keeping perhaps the 100-day and six-month marks as favourites. If you are wondering how the two systems fit together, we wrote a full breakdown of the difference between a monthsary and an anniversary.

Honest answer: the one your relationship already speaks. If you are in India or the Philippines, monthsary will feel natural. If your partner grew up on American internet, monthiversary might land better. If you are both linguistics enthusiasts, mensiversary is a flex and a love letter at once.

The word matters less than the counting. A monthsary is really just a checkpoint on a number that keeps growing — the days you have been together — and that number is the romantic part. That is exactly what CountingUs is for: a beautiful live counter of your days together that you can check on every monthsary, whatever you call it, and a keepsake QR page you can gift on the big ones.

So post the caption with confidence. Monthsary, monthiversary, mensiversary — your relationship is not a spelling test. The only thing worth getting exactly right is the date you started counting from.