Cailo vs Theodore

Baby Name Comparison — 2026

Cailo

Boy #15,816 Most Popular 2 Syllables

Meaning

"rejoice, happy"

Origin: Welsh / Latin Gaius

Cultural Roots

English Welsh Modern American

Quick Stats

Popularity Rank
#15,816
Total SSA Count
7
Syllables
2
Formality
Casual
Nicknames
Kai, Cai, Kay

Playground Safety Score

✓ All Clear
Full profile for Cailo →

Popularity Comparison

Cailo Rank #15,816
Theodore Rank #4

Theodore is more popular, ranked #4 vs #15816 for Cailo.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Cailo ___

  • Cailo James
  • Cailo River
  • Cailo Fox
  • Cailo Reid
  • Cailo Jude
  • Cailo Finn

Theodore ___

  • Theodore James
  • Theodore William
  • Theodore Alexander
  • Theodore John
  • Theodore Henry
  • Theodore Arthur

Sibling Name Ideas

Names that pair well as siblings.

If you choose Cailo

Zara Mila Nova Lyra Axel

If you choose Theodore

Olivia Charlotte Amelia Eleanor Oliver

Which Name Fits Your Family?

Answer 3 quick questions and we'll help you decide.

1. Which style feels more like your family?

Frequently Asked Questions

Is Cailo or Theodore more popular?

Theodore is more popular, ranked #4 compared to Cailo at #15816 in the United States.

What do Cailo and Theodore mean?

Cailo means "rejoice, happy" (Welsh / Latin Gaius origin). Theodore means "divine gift" (Greek origin).

Are Cailo and Theodore boy or girl names?

Cailo is primarily a boy name. Theodore is primarily a boy name.

More Comparisons

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← Full profile: Cailo ← Full profile: Theodore Browse all baby names