Cai

♀ Girl

Pronounced KY /ˈkaɪ/High

Meaning: A Welsh form of Kai — variously 'rejoice' (Welsh) and 'the sea' (Hawaiian kai); used for both sexes; here for girls; routes layeredLow

In 30 seconds: Rejoice; the sea: Cai is a Welsh Kai — 'rejoice; the sea'. Crisp, modern, and warm. Used for both sexes (here for girls).

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Origin LowWelsh, Hawaiian

MeaningA Welsh form of Kai — variously 'rejoice' (Welsh) and 'the sea' (Hawaiian kai); used for both sexes; here for girls; routes layered

U.S. rank (2025)#8457 ↘ Falling

2025 U.S. births12 girls (0.00% of U.S. girls)

Peak year2020

Total births (all-time)≈ 493

Popularity in the U.S. · SSA data

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

SSA data updated May 2026. How we source & verify this data.

History & Origin

Cai is a Welsh form of Kai — variously 'rejoice' (Welsh) and 'the sea' (Hawaiian kai; routes layered, which we note). In Welsh legend Cai was one of King Arthur's earliest companions. A crisp, modern name, used for both sexes, here for girls (slug distinguished).

It registers thinly for girls. Rare, rejoice-or-the-sea at the root, and crisp.

Did you know? Cai is a Welsh form of Kai — variously 'rejoice' (Welsh) and 'the sea' (Hawaiian kai) — a crisp, modern one-syllable name, used for both sexes (here for girls; the routes are layered, which we note; said 'KY').

Overall data confidence 42%

References — Cai — routes layered

Variations

KaiCeiCae

Nicknames

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If you like Cai…

Kai— the common spelling

Mai— a sound-neighbor one-syllable girls' name

Rae— a fellow short unisex girls' name

Skye— another short nature girls' name

Explore names like Cai

By themeuncertain unisex welsh hawaiian

By meaningSea / Water Snow / Winter

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Frequently Asked

What does the name Cai mean?

Cai is a Welsh Kai — variously 'rejoice' and 'the sea'; the routes are layered.

How do you pronounce Cai?

It's said KY /ˈkaɪ/ — one syllable.

Is Cai a boy or girl name?

Cai is used for both sexes; this page covers its use as a girl's name.

How popular is Cai?

Cai is a rare name for girls in the U.S.