Name Spellings, Initials and Sounds
Cool Names with a Strong O
Across 16 pages
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About this list
Baby names that begin or end with the letter O have long been particularly cool, especially (though there are a few feminine selections) for boys. The most popular girl name in the US, Olivia, has a strong O beginning, as does its rising masculine counterpart, Oliver. Both names are extremely popular throughout the Western world.
Along with Olivia and Oliver, other cool names with a strong O in the US Top 250 include Arlo, Diego, Enzo, Leo, Mateo, Milo, Olive, and Theo. Names with multiple Os may be especially cool — such as Apollo, Oona, Otto, and Rocco.
The options for cool names starting or ending with O range far beyond those offered here, of course, especially considering the entire world of Latinate baby names out there, but this group should give you a pretty good start.
The names
Olivia
Latin
"olive tree"
Olivia, a lovely Shakespearean name with an admirable balance of strength and femininity, is one of the top girls' names around the world. 2025 marked its 7th consecutive year in the #1 spot in the…
Oliver
Germanic, Latin
"elf army; ancestor's relic; olive tree"
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…
Mateo
Spanish
"gift of God"
Mateo is a Latinate name that like Mia and Luca, is becoming popular far beyond its native Spanish community. With its fresh feel and charm, it made a surprise entrance to the boys' Top 10 in 2023.…
Leo
Latin
"lion"
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. Brave but sparky, Leo has ranked in the Top 20 in the US,…
Owen
Welsh
"young warrior; well-born"
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. Why do so many parents love Owen? It's a classic with a genuine…
Enzo
Italian variation of Heinz or Henry, German, or diminutive form of -enzo names, "estate ruler"
"estate ruler"
Internationally popular, Enzo is a confident and captivating name, playful but down to earth. Similar in sound or style to the likes of Leo, Luca, Eli, and Ezra, and in tune with Mateo, Gabriel, and…
Theo
Diminutive of Theodore
"gift of God"
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. Now in the Top 100 in this form, Theo's…
Leonardo
Italian and Spanish variation of Leonard, German
"brave lion"
For centuries this name was associated primarily with the towering figure of Italian Renaissance painter-scientist-inventor Leonardo da Vinci, and was scarcely used outside the Latin culture. But…
Lorenzo
Italian; Spanish, variation of Laurence
"from Laurentium"
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…
Milo
Latin and Old German
"soldier or merciful"
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…