Rex vs Ao

Baby Name Comparison — 2026

Rex

Boy #793 Most Popular 1 Syllable

"king"

Origin: Latin

English Latin American

✓ All Clear

Boy #14,516 Most Popular 2 Syllables

"blue, blue-green"

Origin: Japanese

Japanese Chinese Maori

✓ All Clear

Rex Rank #793

Ao Rank #14,516

Rex is more popular, ranked #793 vs #14516 for Ao.

Is Rex or Ao more popular?

Rex is more popular, ranked #793 compared to Ao at #14516 in the United States.

What do Rex and Ao mean?

Rex means "king" (Latin origin). Ao means "blue, blue-green" (Japanese origin).

Are Rex and Ao boy or girl names?

Rex is primarily a boy name. Ao is primarily a boy name.