No longer tied to the hapless Ace Ventura, this jaunty, high-flying nickname name is starting to take flight among celebrity and other parents, with its countless positive references to doing well in tests and poker games, on the tennis court and golf course, and in the air.
 Natalie Appleton, Tom Dumont, Jennie Finch, and Jessica Simpson all have little Aces. The best known grownup with the name is Ace Frehley, born Paul, one-time KISS guitarist.

A name known in several cultures, also through animated book character Tiger Aki.  Finnish author Aki Ollikainen is another notable bearer.

A Welsh saint, the son or grandson of a local king called Caw/Cai. It seems that Caian may be a derivative of that name, which is derived from Caius "rejoice". A church at Tregaian in Anglesey is named for St Caian.

Caian

Caius is classical and serious but also has a simple, joyful quality. There was a third century pope named Caius, as well as an early Christian writer, several Shakespearean characters, and a Twilight vampire. We would pronounce the name to rhyme with eye-us though at Cambridge University in England, where it's the name of a college, it's pronounced keys. 
 Nickname Cai is a definite asset.

Caius

One of the most romantic of appellations, Caspian is a geographical name referring to the large salty sea between Asia and Europe. It's also the name of the hero of C.S. Lewis's beloved Chronicles of Narnia, Prince Caspian. 
 
The name Caspian is ultimately derived from the Latin term Caspii, meaning "white." Caspii was the name of the people of Central Asia who were originally from Caucasus. 
 
Caspian is attracting a lot of attention from cutting-edge parents these days. It fits in with several trends as a name from classic children's literature, a water-related place name, and an ancient name with the trending Cas- beginning, ala Cassius and Cassian.

Caspian

This evocative short name is suddenly chic — it was recently chosen by Jennifer Lawrence for her baby boy. JLaw's son's name honors Cy Twombly, the influential mid-century American artist. Born Edwin Parker Twombly Jr., both Cy Twombly and his father shared a nickname after baseball player Cy Young (himself born Denton True Young).
 
We foresee Cy heating up in a big way, along with other Cy- names like Cypress, Cyan, and Cyra.

With its sharp, succinct sounds and cool, laidback style, Eli is a popular choice among parents today. Compact and punchy, it is a Biblical name with plenty of charm. 
Derived from the Hebrew ’aly, the name Eli means “high” or “ascended.” In the Old Testament, Eli was a high priest of the Israelites, who trained and gave guidance to the prophet Samuel. 
While the Biblical Eli suffered an unhappy end due to his sons’ misdeeds, his name hasn’t shared the same fate. Used since the 17th century, Eli has never been out of the US Top 1000. It has featured in the Top 100 for the last decade, and is currently popular in the UK, Australia, New Zealand, and The Netherlands too. 
Eli is also used as a shortened form of Elijah, Elias, Eliezer, or even Elliot and in some Scandinavian countries, is it used as a feminine name, most often as a nickname for Elisabet or Elin. With its unisex potential and its longer forms ranking highly, Eli might feel more popular than it actually is. 
Notable namesakes include Eli Whitney, the inventor of the cotton gin, Eli Long, a Civil War general, and Eli Roth, a film director, screenwriter, and actor. Enjoyed by the general public and celebrities alike, Eli has been chosen by CNN anchor Campbell Brown, SNL alum Rachel Dratch, and actor Kevin Weisman. 
Spirited but solid, no-fuss Eli is given to over 4000 boys each year, so you wouldn’t be alone in loving the name. If you don’t want your baby to have share however, you could consider other Biblical E names such as Eben, Elim, Enosh, or Eran, or perhaps other 3 letter gems, like Ira, Ari, Jem, Nye, or Ivo.

Finn is a name with enormous energy and charm, that of the greatest hero of Irish mythology, Finn MacCool (aka Fionn mac Cuumhaill), an intrepid warrior with mystical supernatural powers, noted as well for his wisdom and generosity. 
 Finn was chosen by cool couple Christy Turlington and Ed Burns for their son, and also by Jane Leeves and Autumn Reeser. Played by Cory Monteith prior to his death, Finn Hudson was a prominent character on Glee.
Other up-and-comers in the same family: Finlay and Finley, Finian and Finnian, Finnegan and Finnigan, and, from Germany, Fynn.

Finn

Ike, once the quirky one-person nickname of President Dwight Eisenhower, has morphed into a cool kid nickname of the early 21st century. 

The rise of Isaac and the stylishness of short down-to-earth nicknames like Max and Gus means that many parents like Ike once again. In the Top 200 (!) at the end of the 19th century, Ike fell off the Social Security Top 1000 by the end of Eisenhower's presidency in the late 1950s.

We do foresee the comeback of Ike, bur probably as a short form of Isaac or Isaiah.

A name of multiple identities: a somewhat soap-operatic single-syllable surname, a homonym for the biblical bad boy Cain, and, when found in Japan and Hawaii, it transforms into the two syllable KA-neh. 

Kane also has multiple meanings: in Welsh, it's "beautiful"; in Japanese, "golden"; and in Hawaiian, "man of the Eastern sky."

Kane

An evocative name brought from Hawaii to the mainland by Keanu Reeves, who was born in Beirut to a part-Hawaiian, part-Chinese father. It moved into the Top 1000 for the first time in over a decade in 2016. Keanu ranks among <a href="https://nameberry.com/popular-names/us/state/hawaii> hawaii's top 100 baby names</a>.

Keanu

This name of three ancient saints, one Wayans brother, and an NFL wide receiver makes an energetic choice.

Keenan

The international popularity of Noah has led to some parents searching for alternatives and the rhyming Koa is now attracting more attention than ever. With it's cool K initial and summery, nature-inspired feel, this punchy three letter name has risen more than 600 places since it entered the US charts in 2017.
 
A Hawaiian name with a fierce meaning, Koa is also a type of tree native to the islands whose wood is favored for building canoes and surfboards. Considered sacred to some, the tree was also used historically to make weapons, making it synonymous with strength and warriors.
 
Given to around 1100 boys in the US in 2023, Koa is also in the Top 500 in the UK, and in the Top 100 in Australia, where it is also associated with the Aboriginal Koa people, whose name possibly comes from a word meaning "west". 
 
Striking the balance between gentle nature name and bold adventurer, Koa was chosen by guitarist Tom Dumont of the band No Doubt, a brother for Ace and Rio, and a name that fits right in with all of the band's stylishly named offspring, Mason, Magnolia, Ruby, Kingston, Zuma, Apollo, Coco, and Saffron. The YouTubers, Family Fizz, also have a son named Koa, who joins sisters Mia, Sienna, and Karma.

A word in the Yankton-Yanktonai and Santee dialects of the Lakota Sioux language, meaning "friend" or "ally", used for one of the main characters in the movie Brother Bear. Also a common Japanese surname or a respelling of the musical name Coda.

Koda

The Koi is a variety of carp especially popular in ornamental gardens in Japan, where they are a symbol of good fortune. In Buddhist culture, the koi is associated with courage. Being one letter away from trendy Kai boosts its prospects as a cool unisex name.

An Asian name that would be easily understood in this country. 

Kwan

With the rising popularity of Kai, this more phonetic spelling has been gaining traction as well. Kye debuted in the US Top 1000 in 2015, and was one of the fastest-rising names of the year in 2016.

Kyler was once a creative solution for 90s parents who enjoyed the sounds of Kyle and Tyler but didn't want to use anything so popular. Now a well-established name on the US charts, it is given to more than 1000 babies every year. 
 
On one hand, Kyler can be seen as a modern invention, created by combining the on-trend sounds of Kyle and Tyler into something new. With this in mind, the meaning would be "tiler of roofs on the narrow spit of land". 
 
Alternatively, Kyler could be an Anglicized form of the Dutch surname "Cuyler ", which may mean "hole, pit", "bowman, archer", "chapel", or "victory of the people" according to different translations.
 
A surname-as-a-given-name, with the on trend sounds of Kai, Kyler became a popular choice from 1986 onwards, when it first debuted in the charts. Remaining in the Top 300 for most of the 2000s, Kyler did drop by 70 places in 2023 - the first time it has fallen so significantly since it entered the Top 1000. 
 
With parents currently favoring Cooper, Colter and Kaizen, Kyler may continue to sink as Kyle did before it - or, it may just be a temporary blip in its popularity.

Kyler

Kyrie may be a name of God used widely in the ancient church refrain Kyrie Elieson, or Lord, have mercy, but it's rising in popularity for boys in the US on the strength of basketball star Kyrie Irving. Irving pronounces the first syllable of Kyrie to rhyme with my, whereas with the religious word it rhymes with fear.

Kyrie

Levi, lighter and more energetic than most biblical names, with its up vowel ending, combines Old Testament gravitas with the casual flair associated with Levi Strauss jeans. 
 Now it's being rediscovered in a major way—Levi has been shooting up the charts in recent years. Extremely popular in the US, it's also a Top 100 name throughout the English-speaking world as well as in a diverse range of countries from Germany to Brazil.
 
In the Old Testament, Levi was the third son of Leah and Jacob, from whom the priestly tribe of Levites descended; in the New Testament, Levi was Matthew's given name before he became an apostle. It is suspected that Levi derives from the Hebrew word yillaweh, meaning "he will join." 
 Levi received a lot of attention as the sons of Matthew McConaughey, Sheryl Crow and Sara Gilbert.
 In the Thomas Hardy novel Far from the Madding Crowd, Levi Everdene is the father of the heroine. 
 <br/
Levon is a related name.

Levi

A nature name from the Hawaiian islands that's vaguely reminiscent of trendy names like Luke and Luca. However, it's also the name of a Swedish company that makes mechanical lifts used in medical settings to move mobility-impaired patients.

Liko

An Old Testament name with a Gaelic lilt, Malachi entered the list in 1987.
 In the Bible, Malachi (pronounced with the final syllable as EYE), was the last of the twelve Hebrew prophets, who foretold the coming of Christ. 
 In Anthony Trollope's Phineas Finn, Malachi is the name of the hero's father, and in James Joyce's Ulysses, Malachi Mulligan is a medical student. The lighter-hearted Irish version is usually spelled Malachy.

Malachi

A name that looks intriguing and masculine on paper, but is, unfortunately, a homonym for a girl's name. 

Quay

A well-used name in China that has some potential for assimilation. 

Quon

A slim, elegant, silvery surname, Reed could be a banker or a sculptor, and therein lies the appeal of this simple yet distinctive name. The versatile Reed can be seen as a grass-like nature name and a musical name.
 There have been Reeds on Grey's Anatomy and Party of Five, as well as on the big screen in Boogie Nights. Reed Richards was the human name of the scientific genius who became Mr. Fantastic of the Fantastic Four.
 The many notables who wore Reed as a surname include army surgeon Walter, basketball coach Willis, Brady Bunch dad Robert, critic Rex, director Sir Carol, actors Donna and Oliver, and singer-songwriter Lou.
The name can also be spelled Reid.

Reed

As a stylish name, Ryker has three big things going for it: its Ry beginning (as in Riley, Ryder, and Rylan), its two-syllable rhythm, and its er ending. A nice surprise for many is it's "rich" meaning. While this may not be a factor beyond New York City, there is an infamous prison there called Riker's Island. Ryker is one of the trendiest <a href="https://nameberry.com/baby-names/494/german-names-for-boys">German names for boys</a> in the US.

Ryker

Sky is an ambigender nature name that was first legitimized as the character of Sky Masterson in the 1950 musical Guys and Dolls, played in the film version by Marlon Brando. It's a name we appreciate for its clear, wide-open feel, less hippyish than others like Rainbow and Starlight, and makes an appealing middle name possibility.
 Sky is the name of Sophie's fiance in Mamma Mia, and there are both Power Rangers and Transformers with the name. Elizabeth Berkley used it for her son.
 It is also spelled Skye, as in the island in the Inner Hebrides of Scotland. Plus, it's a logical nickname for the variously spelled Schuylers and Skylers.

Tai, which rhymes with Kai, is a unisex name with a range of international references.  It means the equivalent of "too much" in Chinese but is also used as a Maori name meaning "the tide" and in Romanian means "yours."  While it's only ever ranked in the U.S. Top 1000 as a girls' name, during the height of the popularity of Olympic skater Tai Babilonia, Tai makes a simple intriguing modern choice for either gender.

As likely to be tied to the detergent as to the rhythms of the ocean. 

Tide

Western novelist Zane (born Pearl!) Grey made this name famous. Now, it's in tune with the style of our times, retaining that appealing cowboy image. 
 Zane Grey was the great-grandson of Ebenezer Zane, founder of Zanesville, Ohio, the town where the writer was born. The name Zane has been on the popularity list since 1921, the heyday of such Zane Grey novels as The Riders of the Purple Sage.
 The Arabic name Zayn, as in musician Zayn Malik, sounds exactly the same as Zane but has a different root. Zayn is one of the fastest-rising names in recent years. And some parents--including country singer Mindy McReady -- use the spelling Zayne.

Zane

slginfj's list "Alternatives to Kai" of 30 great name ideas: Ace - Zane!

Alternatives to Kai

Below is a list of substitutes for the masculine name Kai. Names include those with similar sounds, similar length, Asian and Pacific Islander origins, and/or an ocean theme.