Baby Name of the Day: Kai

The baby name Kai brings to mind a medieval knight and a modern surfer.

Thanks to Clio for choosing our Baby Name of the Day.

WHAT DOES THE NAME KAI MEAN?

The meaning of Kai is tough to pin down. Not because there’s no answer, but because dozens of possible origins and meanings compete.

Back in the earliest tales of King Arthur and the Knights of the Round Table, we find Sir Kay, foster brother to the king. Sometimes he’s brave and loyal; later tales make the character boorish. 

The knight’s name changes, too. Over the years and across languages, Kay becomes Caius, Keu, Kes, Kex, Kei, Cai, and yup, Kai. 

The Latin Caius suggests a link to the Gaius, as in Gaius Julius Caesar. If that’s true, then Kai means to rejoice, from the Latin gaudeo. Or maybe the similarity is coincidental.

Another meaning sometimes associated with Kai? Keeper of the keys. That comes from Arthurian legend, too. In some tellings, Kay serves as his foster brother’s seneschal. It’s a significant position in a royal household, but it’s only of many takes on the character.

This version of the name dates the name to the tenth century or so. Cai remains in use as a masculine name in Wales.

KAI AS A NICKNAME

The baby name Kai might also be short for Cornelius, Nicholas, and other longer names.

The German form of Nicholas is Nikolaus; in Dutch, it’s Nicolaas. But the name has Greek roots. If that explains the origin of the name Kai, then it means “victory of the people.” It’s a cousin to Colin, Nico, and Cole.

On the other hand, the English and German Cornelius becomes Cornelis in Dutch. The New Testament name might mean horn, but it’s not clear.

Some suggest that the nickname has Frisian roots – a group of languages spoken in Germany and the Netherlands. It might connect to the Frisian word kaimbe, meaning warrior. As with Gaius, it’s not clear if it explains the name’s roots, or is just a happy coincidence.

There’s also Gerhart, the German, Dutch, and Scandi form of the name we know best as the French Gerard or Spanish Gerardo. The name comes from elements meaning brave spear. While the link between Gerhart and Kai feels harder to make, it’s one of a multitude of origins suggested.

KAI IN SCANDINAVIA

Farther north, the name is also spelled Kaj and Caj.

The most famous example comes from Danish writer Hans Christian Andersen.

Andersen penned “The Snow Queen” back in 1845. The story goes like this: the devil himself crafted a mirror to distort reality and make us see the world as ugly and cruel. It shattered into millions of pieces, and now we can get splinters in our eyes and hearts.

Best friends Kai and Gerda grow up as close as siblings. But as they grow, Kai falls victim to the splinters, and is taken captive by the Snow Queen. His family believes he has died, but Gerda never gives up. After an epic journey by reindeer, she finds him in the Queen’s permafrost castle, and frees him with her love.

The original version of this post, from 2013, read:

… heard that Disney was making an adaptation of the fairytale. It could be a huge boost for Kai! Except it looks like Frozen is a complete reinvention of the story, with no character by the name.

As it turns out, Frozen did give us a Snow Queen, and a reindeer, and a rescue based on love. But the rest of the story is very different indeed.

The baby name Kai didn’t get a Disney boost. But by the time Frozen came out, it didn’t need one.

AROUND THE WORLD

It’s easy to make the case for this name emerging in different cultures and languages.

Keep digging, and some connect the baby name Kai to:

• Cajetan, ultimately from Caieta or Gaeta, the name of a town in ancient Italy. Caietanus and Cajetanus appear over the years, too.
• In Japan, the ancient province of Kai is known today as Yamanashi Prefecture. It’s west of Tokyo in Honshū. In this case, the meaning of the name is unknown. However, the sea is deeply embedded in Japanese culture.
• Depending on the kanji, it might mean ocean or earth in Japanese.
• Along the same lines, in Chinese, it could mean victory.

And, of course, the sound brings to mind boys’ names from 90s favorite Kyle to the Biblical Malachi. The spelling Malakai also ranks in the US Top 1000 today.

NATIVE AMERICAN ORIGINS

Other sources suggest Native American origins, typically “willow tree” in Navajo. While the translation for the word is correct, it’s not clear if it would be perceived as a given name.

HAWAIIAN BABY NAME KAI

Despite these varied international ties, the baby name Kai is linked most strongly to Hawaii, where it means sea. It appears in compound names, masculine and feminine, like Kainoa and Kailani.

That puts the baby name Kai in the same category as River. Hawaiian culture draws most of its personal names from the natural world.

It first climbed in the 1950s, when Kai Winding, a Danish-born jazz musician, rose to fame. He recorded Time is On My Side before the Rolling Stones.

But here’s a better answer for Kai’s emerging popularity: in 1959, Hawaii became the 50th state.

Pop culture took notice. Elvis starred in Blue Hawaii in 1961, followed by two more movies featuring the singer donning leis and cavorting on beaches. A handful of television shows were set there during the 1960s, too.

Then came Hawaii Five-O, a major prime time phenomenon from 1968 through 1980.

None of them gave us a leading man by the name, but several of the episode titles included the word Kai. 

There was a Hawaiian actor named Lani Kai – born George Woodd – who had a role in everything from Blue Hawaii to Hawaii Five-O.

And the word for “sea” is everywhere in the island state, appearing in place names and character names, too.

Perhaps as more Americans vacationed in the new state or served at the island’s multiple military bases, the baby name Kai started to sound more familiar and accessible.

By 1979, it had tipped into the Top 1000.

Another factor? At the time, Kyle was a fast-rising Top 100 boys’ name. The baby name Kai sounded right.

KAI IN POP CULTURE

Celebrities embraced the baby name Kai for their children.

NPR journalist Kai Ryssdal helped put the name in the spotlight. Ryssdal’s father is Norwegian, and the Marketplace host spent part of his childhood in Denmark.

Beginning in 2011, Lego series Ninjago gave us an animated ninja by the name.

Television characters abound, including The Vampire Diaries‘ baddie Malachai “Kai” Parker.

The Kung Fu Panda series gave the name to a villainous yak, General Kai. 

South Korean singer, dancer, and actor Kai is familiar to K-Pop fans. 

It’s gently trended unisex over the years, too. That’s consistent with the name’s use in Hawaiian, as well as recalling Kylie and Kyla.

HOW POPULAR IS THE NAME KAI?

Over the past decade, the baby name Kai climbed into the Top 100 in the United States. It peaked at #59 in 2022 and ranks #76 as of 2024. 

It’s now among the most mainstream of baby names, a solid 21st century choice for a son.

In addition to Kai, related names include:

• Kaiden at #207, thought that’s likely pronounced Kayden, rhymes with Aiden
• Malakai at #233
• Kairo at #238; Kyro is #643 and Cairo is #355
• Kaizen at #506
• Kaison at #513, again possibly pronounced Kayson to rhyme with Grayson; Kyson is #465
• Makai at #535
• Zakai at #603
• Jakai at #647
• Kaiser at #799
• Kaisen at #899
• Khai at #947

Adding in Ky- names would double the list. The baby name Kai also opened the door for lots of names ending with AI, like Azai, Kenai, and Sarai.

In Hawaii, the baby name Kai currently ranks #7. Names Kaimana, Kainoa, and Alakai also rank in the Top 100 for boys, as well as Kaia, Kaila, Kailani, and Kailea for girls.

IS KAI A GIRL’S NAME?

Given the many origins and multiple meanings of the name Kai, it’s no surprise that we hear it across gender lines. From 2010 to 2023, the baby name Kai appeared in the girls’ Top 1000, too. 

It is expressly unisex in Hawaiian.

In other languages, like Estonian, Kai is short for forms of Katherine, as is Kaia, which follows logically from Katarina.

21st CENTURY STYLE STAR

File the baby name Kai with the Sweet Spot names. It’s not too traditional, nor does it feel invented. And while the name continues to enjoy some popularity, it’s still far from the Top Ten. 

Kai makes for a great, modern choice for a son. International, but still casual, Kai feels at home on a surfboard. And yet the name could suit anyone, from a noble knight to a 21st century world traveler. If you’re looking for something current, brief, and worn by heroes from across many cultures, Kai could be the perfect name. 

What do you think of the baby name Kai?

First published on October 2, 2013, this post was revised substantially and re-published on January 30, 2019. Further uptakes took place on April 6, 2022; March 21, 2023; and November 19, 2025.