Begins or Ends with O

Milo is most commonly considered to be Germanic name derived from the Latin word miles, meaning "soldier." However, there is evidence to suggest it also may have independently spawned from the Slavic root milu, meaning "merciful." Milo predates brother name Miles, a variation that evolved when the name immigrated to the British Isles in the Middle Ages. Mylo is an alternate spelling.

Oscar is one of the most stylish Old Man Names of our era. While it's softened slightly in popularity over the past 20 years, that may be considered a very good thing.

Hugo, the Latin form of Hugh, has more heft and energy than the original -- and of course we love names that end (or begin, for that matter) with an o. This one is especially appealing because it's backed up by lots of solid history and European style.

Leo is a strong-yet-friendly name that was common among the Romans, used for fourteen popes, and is now at its highest point ever in the US thanks in part to Leonardo "Leo" DiCaprio.

Oliver is an international star, ranking near the top of the charts throughout the English-speaking world and in a host of European and Latin American countries, from Norway to Chile, Slovenia to Switzerland. Why? Because Oliver is energetic and good-natured, stylish but classic, with a meaning symbolizing peace and fruitfulness.

Owen, a resonant Celtic name, has ranked among the Top 100 boys' names in the US for 20 years and is now at its highest point ever.

Quirky cool Arlo is now well and truly back. Last year it broke into the US Top 200 boy names and consistently ranks among the most popular boy names on Nameberry.

See the popularity graph below for the name Theo? It's been heading straight uphill since 2010, when it hopped back onto the Top 1000 after a 60+ year absence.

Otto is cool again. Long a quintessential Old Man Name, Otto has been promoted to trending darling of adventurous baby namers.

With a touch of celestial power, a hint of clunky charm, and the totally cool -o ending, Cosmo may well be finally shaking itself free of both the Seinfeld association (which made it a punchline of a joke) and the cartoon fairy association from The Fairly OddParents. In fact, it is in the Top 1000 in the UK and a favorite on Nameberry.

Orion is a rising star, with both mythical and celestial overtones.

Beau suggests someone devilishly handsome, with a large measure of southern charm—a nice image to bestow on your boy. Often solely a nickname in the past, it's now standing firmly on its own. Beau has been on the Social Security list non-stop since 1969.

Succinct, stylish, and catchy, Ivo has the energetic impact of other names ending in -o. It is a multicultural choice with two distinct origins, and, as such, is familiar across a variety of countries, ranging from the Netherlands to Brazil, from Portugal to Czechia.

This attractively energetic Italian version of the classic Matthew is primed to move further and further into mainstream American nomenclature. Mateo is technically the Spanish version, but many parents in the US use the two spellings interchangeably.

With mythological names rising, the handsome son of Zeus and god of medicine, music, and poetry among many other things might offer an interesting, and melodic option. Similar in style to Atlas and Atticus and similar in sound to Arlo, Paolo, Paul, and Ollie, Apollo entered the US Top 1000 back in 2012, and was propelled upwards after it was chosen by Gwen Stefani and Gavin Rossdale in 2014.

Cute but cool, fresh but familiar, Ozzy was one of the fastest-rising boy names of 2021 and has continued to rise in the US and the UK ever since. While hard-core rocker Ozzy Osbourne might not be everyone's idea of a role model, his nickname name, along with others like it (think Iggy, Ziggy and Izzy) are forging their own way up the charts.

Soft and sensitive name often heard in Israel.

Popular in Croatia, Spain, New Zealand, and Slovenia, Niko has also been rising up the US popularity charts for boys since the late 2000s. Fresher than Nicholas, spikier than Nico, it currently ranks just outside the US Top 300.

Dashing and suave, with a hint of poetry and gentleness, Emilio is an appealing and international choice. A solid favorite in Italy, it is also on the rise in the US, France, Austria, and the UK.

Latinizing Lawrence gives it a whole new lease on life. Like Leonardo, Lorenzo has been integrated into the American stockpot of names, partly via actor Lorenzo Lamas. Other associations are with Lorenzo de' Medici, the Florentine Renaissance merchant prince and art patron, Renaissance artists Ghiberti and Lotto, and the upstanding young man who married Shylock's daughter Jessica in Shakespeare's The Merchant of Venice.