The baby name Cosmo is out of this world … and completely down to earth, too.
Thanks to Lola for suggesting our Baby Name of the Day.
WHAT DOES THE NAME COSMO MEAN?
The Greek kosmos originally meant “orderly arrangement.”
Sometime around the 6th century BC, ancient Greek philosopher Pythagoras used the word to refer to the universe as a whole.
Today, cosmos continues to refer to the world in the widest sense. Cosmic refers strictly to the stars and objects in the solar system and beyond.
And if you’re cosmopolitan? Then you’re someone at home anywhere. Though a closer synonym for cosmopolitan is sophisticated, not astronaut, so there’s a slightly different vibe.
You might hear the baby name Cosmo and think of two things:
- Cosmo, the women’s magazine, debuted way back in 1886.
- And the cocktail? An early version was created way back in the late 1920s, but the drink reached its current form in the mid-1980s and became famous thanks to the long-running Sex and the City series.
It’s been a given name for even longer.
SAINT COSMO
During the 3rd century, brothers Cosmo and Damian used their medical training to help those too poor to afford services.
They died as Christian martyrs during the Diocletian persecutions. They’re both considered saints.
Just like any saint’s name, it spread across the Western world. Other forms evolved:
- The saint was probably named Cosmas.
- It became Cosimo in Italian. The powerful de Medici Renaissance family embraced it.
- During the 1700s, the Duke of Gordon named his son Cosmo, bringing it to broader use in the English-speaking world.
In fact, British Cosmos pop up in the history books from the 18th century onward.
Where did a Scottish aristocrat find an Italian name? The Duke’s dear friend was Cosimo III de’ Medici, Grand Duke of Tuscany, who reigned for a record-setting 53 years. It’s worth noting that the Tuscan ruler was something of a disaster.
But that’s so far in the distant past that it doesn’t touch the baby name Cosmo now.
20th CENTURY COSMO
By the 20th century, the name read less as a saintly, pan-European choice and more as an offbeat, unexpected character.
- In 1926 novel turned 1937 movie Topper, staid banker Cosmo Topper has his life transformed by a pair of fun-loving ghosts, played by Constance Bennett and Cary Grant. Sequels followed. Remakes, too, the most recent in 1979.
- The cast of 1952’s Singin’ in the Rain included Cosmo, the comic foil played by Donald O’Connor to leading man Gene Kelly and newcomer Debbie Reynolds.
- Brigham Young University’s mascot is Cosmo the Cougar.
- If you know your Nickelodeon animated series, the long-running Fairly OddParents featured Cosmo and Wanda as Timmy Turner’s fairy godparents.
- One more from the world of animation: Cosmo Spacely served as George Jetson’s demanding boss at Spacely Sprockets on cartoon The Jetsons.
- To Seinfeld fans, it’s all Cosmo Kramer, the resident of Apartment 5B.
NATURE NAME
Typically known as cosmos, the flower in a cousin to the daisy. Varieties are found throughout the Americas and beyond.
Scarlett Johansson and Colin Jost named their son son Cosmo in 2021. He joins older sister Rose from Scarlett’s first marriage. In some respects, the siblings’ names are very different, but they’re linked by their subtle botanical meaning.
ARLO, LEO, THEO, MILO
Boy names ending with o have gone from rising style stars to mainstream favorites. As of 2025, the US Top 100 includes Mateo, Leo, Thiago, Enzo, Theo, and Theodore, as well as Beau.
Names like Milo, Arlo, Hugo, and Nico aren’t far behind.
In this company, the baby name Cosmo feels only slightly daring.
HOW POPULAR IS THE NAME COSMO?
The baby name Cosmo dipped into the US Top 1000 just a handful of times during the 1910s and 20s.
As of 2020, 57 newborn boys received the name. That’s a leap from just 22 in 2000, or 25 in 2010. But it’s still incredibly rare, too.
The baby name Cosmo appears in the US Top 1000 just four times, in 1913, 1921, 1925, and 1926.
It reached peak popularity with 99 births in both 2022 and 2024. As of 2025, the name was given to just 80 boys.
This just under-the-radar status reinforces Cosmo’s quirky charm.
WORLDLY and UPBEAT
Cosmo bridges the familiar and the distinctive. It blends a long history of use, an appealing meaning, and plenty of current style.
If you’re after a truly uncommon blends-in/stands-out choice for a son, Cosmo might be worth a closer look.
What do you think of the baby name Cosmo?
First published on June 29, 2008, this post was revised substantially and re-posted on September 17, 2012; August 19, 2021; and October 21, 2026.
I have long loved Cosmo – likely influenced by Cosmo Cougar and Cosmo Brown from Singing in the Rain, and cosmology and cosmonauts are also nice associations – but just in the past week or so I’ve started thinking of it as possibly usable so I was a little excited and nervous when I saw this profiled today.
Our grandson “Cosmo” is all of the above mentioned. He is witty, very strong, noble and caring. We love him and his name. We have had so many surprised looks when have introduced him as “Cosmo>,,When our daughter told us that she was going to name him Cosmo we immediately thought of St.Cosmo.,
We love the name “Cosmo” after all he is our grandson
My brother’s second of two middle names is Cosmo. It’s the name he goes by as his first name is the same as our dad’s (& his dad’s etc), and first middle name is same as my our maternal grandfather. I don’t think I’ve met other people named Cosmo, and people get a kick out my brother’s name. Having a brother with such a distinct name is fun, and sometimes handy (when I meet people who mention someone named Cosmo, I know they are talking bout my brother!).
I love Cosmo! It’s such a fun and quirky name! The first thing that comes to my mind is the Fairly Oddparents show (that’s what you get when you have kids :)). Not a bad association though, I’ve always loved Cosmo; he’s so cute and funny. I think Cosmo would make a great middle name; it’s a bit much for a first name IMO.
DH, I take your point – marketing guru Cosmo Jones sounds fabulous, but Officer Cosmo Harris seems a bit less credible.
Still, I think it’s an interesting, appealing choice – especially if you’ve got a Cosmo on your family tree! For me, I think I’m partial to the feminine form Cosima – Nigella Lawson has a daughter called Cosima. (And a son Bruno!)
Catherine, that’s an interesting idea – the personality multiplier. I’m off to dust off my copy of the BN Wizard and see if I can find the reference. It’s one of the tricky things of naming babies – my mother is a shy, stick-to-the-shadows type with a flamboyant name. And so she gave me the kind of ordinary moniker she’d have preferred – only to discover that she’d given birth to a spotlight-lovin’ show-off. If we could only swap, we’d both be happy. As I prepare to give my own daughter-to-be an unusual moniker, I wonder if I’ll doom her to be a wallflower. 🙂
I think it’s a fun name, but maybe a little too much fun? I guess the Seinfeld association is really strong for me, but I’d have a hard time taking Cosmo seriously. A great name if you’re a comedian or an artist or an entrepreneur but a bit of a burden if you’re an accountant, a judge, a police officer.
Woo Cosmo! Well, being a little younger, my first association is the Nickelodian (sp?) show Fairly Oddparents. Cosmo and Wanda are fairy godparents, and Cosmo’s a few crayons short of a whole box, so. However, I quite like the name. It’s fun and distinctly masculine. However, I read somehwere, I think it was in the Baby Name Wizard, that it’s a “personality multipler.” If your kid is named Cosmo and he’s cool, he’s 10 times as cool. But if poor Cosmo is fat or pimply or socially awkward, you don’t have quite as much luck. On a wholly personal level, it’s on the like but wouldn’t use, except as maybe a middle name somewhere down the line. I’d like to use more use though. It’s such a fun name!
Oh, and rocker Beck and his wife (Marissa Ribisi) have a little Cosimo (Cosimo Henri)! So how far off track would simpler Cosmo be? 🙂
You’ve hit on exactly the things I encounter when asking about my Great Grandpa’s name online. I find Cosmo to be rather new-agey and yes, even spacey but friendly and warm too. Expansive feeling (the whole Cosmos, hmm?) 😀 Beyond G Grandpa, it reminds me of Carl Sagan too. Beacuse of the space thing. And that’s okay by me. I like outer space. One of the two great mysteries left us (Underwater is the other). I find Cosmo to be happy, easygoing and masculine. Easy to spell, too. That’s a hard set of things to be, I think. There aren’t many names that “feel” the same to me. Cosmo will definitely be the boy name, if we have another. I find him far too charming to backburner yet again. To heck with everyone else, this is what works, for us. 🙂