Callister vs Theo

Baby Name Comparison — 2026

Callister

Boy #43,579 Most Popular 3 Syllables

"defender of men"

Origin: Greek via Gaelic

Scottish Manx Irish

✓ All Clear

Boy #80 Most Popular 2 Syllables

"gift of God"

Origin: Greek (theodoros)

English Greek French German American

✓ All Clear

Callister Rank #43,579

Theo Rank #80

Theo is more popular, ranked #80 vs #43579 for Callister.

Is Callister or Theo more popular?

Theo is more popular, ranked #80 compared to Callister at #43579 in the United States.

What do Callister and Theo mean?

Callister means "defender of men" (Greek via Gaelic origin). Theo means "gift of God" (Greek (theodoros) origin).

Are Callister and Theo boy or girl names?

Callister is primarily a boy name. Theo is primarily a boy name.