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Cailyn

♀ Girl

Pronounced KAY-lin /ˈkeɪ.lɪn/High

Meaning: Modern blend of Kay — from Katherine, 'pure' — and -lyn, from Welsh llyn, 'lake'Medium

In 30 seconds: A C-spelling in the big Kaylin family — Kay plus Lynn with a faint Irish echo of Caoilfhionn, 'slender and fair'. Familiar sound, less familiar look.

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Origin MediumAmerican, Irish

MeaningModern blend of Kay — from Katherine, 'pure' — and -lyn, from Welsh llyn, 'lake'

U.S. rank (2025)#3728 ↘ Falling

2025 U.S. births40 girls (0.00% of U.S. girls)

Peak year2009

Total births (all-time)≈ 5,549

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

Cailyn is one of the many spellings — Kaylin, Kaylyn, Caelyn, Kaelin — of a modern blend built from Kay, the Katherine-derived classic meaning 'pure', and -lyn, the lake-born Welsh suffix. Some parents and name dictionaries also tie the sound to Irish Caoilfhionn, 'slender and fair', the name of an early saint.

The Kaylin sound flourished in 1990s and 2000s America as part of the broader Kay- boom. The C-spelling gives it a softer, slightly Gaelic look and has always been among the rarer forms.

Did you know? The medieval Irish saint Caoilfhionn — whose name anglicizes to Keelin and influences names like Cailyn — bore a name meaning 'slender and fair'.

Overall data confidence 78%

Behind the Name — Kaylyn — blend etymology

Variations

KaylinKaylynCaelynKaelin

Nicknames

CaiLynnie

Famous Bearers

Famous bearers coming soon.

If you like Cailyn…

Kaylin— the standard spelling of the same blend

Kaitlyn— the bigger sister name that drove the Kay- fashion

Caitlin— shares the Irish C-spelling sensibility

Jazzlyn— another modern pick

Paityn— shares Cailyn's American roots

Explore names like Cailyn

By thememodern blend irish-flavored

By meaningSea / Water Purity

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Frequently Asked

What does the name Cailyn mean?

Cailyn is a modern blend of Kay, from Katherine, 'pure', and -lyn, 'lake'; it is also linked by some to Irish Caoilfhionn, 'slender and fair'.

How do you pronounce Cailyn?

It's said KAY-lin /ˈkeɪ.lɪn/ — two syllables, stress on the first.

Is Cailyn a boy or girl name?

Cailyn is a girl's name.

How popular is Cailyn?

Cailyn is a rare spelling in the U.S.; Kaylin and Kaylyn are the more familiar forms.