Cai

♂ Boy

Pronounced KAY /ˈkeɪ/Low

Meaning: Welsh masculine name derived from the Latin Gaius/Caius, borne by Cai (Sir Kay) of Arthurian legend. (As a separate Chinese name it can mean 'colourful' or be the surname Cai.)Low

In 30 seconds: Cai is a Welsh boy's name drawn from the Latin Gaius, borne by Sir Kay of Arthurian legend.

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Origin LowWelsh, Latin

MeaningWelsh masculine name derived from the Latin Gaius/Caius, borne by Cai (Sir Kay) of Arthurian legend. (As a separate Chinese name it can mean 'colourful' or be the surname Cai.)

U.S. rank (2025)#2113 ↘ Falling

2025 U.S. births69 boys (0.00% of U.S. boys)

Peak year2022

Total births (all-time)≈ 1,450

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

The Welsh Cai comes from the Latin Gaius or Caius and is the name of Cai — Sir Kay — one of King Arthur's knights. That Arthurian link gives it deep roots in Welsh tradition. As a separate Chinese name, Cai can mean 'colourful' or stand as the surname Cai, so the same three letters carry two unrelated stories.

Short and sharp, the Welsh Cai is usually said to rhyme with 'eye', keeping the legend of Sir Kay close at hand.

Did you know? Cai is the Welsh form of the Latin Gaius/Caius and is famously borne by the mythological Sir Kay of Arthurian legend, which gives the name its enduring appeal.

Overall data confidence 55%

Behind the Name - Cai — etymology, usage, pronunciation, and related formsU.S. Social Security Administration — 2024 popularity rank and count supplied in the batch input CSV

Variations

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Nicknames

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Famous Bearers

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If you like Cai…

Caius— The alternate Latin spelling that Cai descends from.

Kai— shares Cai's Welsh roots

Cru— another Latin name

Cam— a fellow Latin choice

Cross— shares Cai's Latin roots

Frequently Asked

What does the name Cai mean?

Cai is the Welsh form of the Latin name Gaius/Caius, also associated with the mythological Sir Kay. It is most often linked with Welsh tradition.

How do you pronounce Cai?

It's commonly said KAY /ˈkeɪ/.

Is Cai a boy or girl name?

In this batch and in recent U.S. usage data, Cai is used as a boy name.

How popular is Cai?

In 2024, Cai ranked #1902 in the U.S. for boys, with 83 births recorded.