Kai

♂ Boy

Pronounced KY /kaɪ/High

Meaning: Sea — from Hawaiian kaiHigh

In 30 seconds: A crisp, one-syllable name meaning 'sea' in Hawaiian, with parallel meanings in Welsh and Japanese. Kai has entered the U.S. top 100 boys' names, loved for its elemental simplicity.

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Origin HighHawaiian, Welsh, Japanese

MeaningSea — from Hawaiian kai

Peak year2017

Total births (all-time)≈ 36,000

Popularity in the U.S. · SSA data

U.S. births per year (Social Security Administration, 1880–present). Pink marker = peak year.

History & Origin

In Hawaiian, kai means the sea or ocean, a powerful elemental concept in Pacific Island culture. In Welsh Arthurian legend, Cai (Kay) is one of King Arthur's knights. In Japanese, kai can mean shell, sea, or food depending on the character used. The convergence of these meanings from completely unrelated language families has made Kai a rare genuinely cross-cultural name.

Kai began appearing in U.S. given name charts in the late 20th century, initially associated with Hawaiian and Asian-American communities, and then broadened significantly as multicultural and nature-inspired short names became fashionable. It entered the U.S. top 100 boys' names around 2010 and has continued to climb, appealing for its brevity, elemental feel, and cross-cultural resonance.

Did you know? Kai appears independently in at least six languages with different meanings — Hawaiian (sea), Welsh (keeper of keys), Japanese (shell/food), Scandinavian (earth), Frisian (warrior), and Greek (Earth) — making it one of the most genuinely multicultural names in use.

Variations

CaiKaj

Nicknames

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Famous Bearers

★Kai Havertz (1999–)
German professional footballer who plays for Arsenal and the German national team.

If you like Kai…

Finn— short, elemental boys' name with Celtic roots and the same punchy appeal

Leo— one-syllable nature-rooted classic in the same crisp, cool tier

Axel— similarly short, energetic boys' name with Scandinavian roots

Miles— one-syllable sophisticated boys' name in the same modern cool category

Frequently Asked

What does the name Kai mean?

Kai means 'sea' in Hawaiian, 'keeper of the keys' in Welsh tradition, and 'shell' or 'food' in Japanese — different roots that converge on the same sound.

How do you pronounce Kai?

It's said KY /kaɪ/ — one syllable, rhyming with 'sky'.

Is Kai a boy or girl name?

Kai is used predominantly as a boys' name in the U.S. but is genuinely unisex in some communities.

How popular is Kai?

Kai has ranked in the U.S. top 100 boys' names since around 2010 and continues to climb.