Caius

♂ Boy

Pronounced KAY-us /ˈkeɪ.əs/High

Meaning: From Latin Gaius (spelling variant Caius), one of the most common Roman praenomina; possible connection to Latin gaudere (to rejoice) though etymology is debated; meaning joy or rejoicingMedium

In 30 seconds: Caius is an ancient Roman praenomen, the spelling variant of Gaius, borne by Julius Caesar himself (Gaius Julius Caesar) and by dozens of Roman emperors and statesmen, meaning rejoice — a name of profound classical antiquity and Roman dignity.

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Origin HighLatin

MeaningFrom Latin Gaius (spelling variant Caius), one of the most common Roman praenomina; possible connection to Latin gaudere (to rejoice) though etymology is debated; meaning joy or rejoicing

U.S. rank (2025)#927 ↗ Rising

2025 U.S. births254 boys (0.01% of U.S. boys)

Peak year2025

Total births (all-time)≈ 2,328

Popularity in the U.S. · SSA data

U.S. births per year (Social Security Administration, 1880–present). Pink marker = peak year.

History & Origin

Caius is the Latin spelling variant of Gaius, one of the most common Roman praenomina (given names). Its etymology is disputed: some scholars connect it to Latin gaudere (to rejoice) or Gaia (earth goddess), while others consider it pre-Latin. The name was borne by Julius Caesar (Gaius Julius Caesar), the emperor Caligula (born Gaius Julius Caesar Germanicus), and many other famous Romans. In English, Caius is the spelling used in Shakespeare's The Merry Wives of Windsor and in medical tradition (Gonville and Caius College, Cambridge).

Caius fell out of everyday use after the Roman era but has been preserved in academic and ecclesiastical tradition. In the 21st century it has attracted interest from parents who want a genuinely ancient Roman name that sounds fresh and distinctive — similar to the revival of names like Atticus, Cato, and Titus. Its two syllables, classical pedigree, and the direct connection to Julius Caesar give it extraordinary historical depth in a brief package. The Twilight film series character Caius (a Volturi vampire) gave the name additional modern cultural visibility.

Did you know? Julius Caesar's full name was Gaius Julius Caesar — meaning his personal (given) name was Gaius/Caius, his family name was Julius, and his branch name was Caesar; the title Caesar eventually became the word for emperor in German (Kaiser), Russian (Tsar), and other European languages.

Overall data confidence 80%

Behind the Name — Gaius — Latin etymology and Roman usage

Variations

GaiusKaius

Nicknames

Cai

Famous Bearers

★Gaius Julius Caesar (100 BC–44 BC)
Roman general, statesman, and dictator whose personal name was Gaius (Caius); he crossed the Rubicon, conquered Gaul, and was assassinated on the Ides of March.

If you like Caius…

Atticus— ancient Roman name with the same classical pedigree and 21st-century literary revival

Titus— two-syllable Latin Roman name with the same ancient dignity and modern revival appeal

Cato— short Latin Roman name with comparable ancient stoic gravity

Magnus— Latin and Scandinavian boys name with the same classical strength and historical weight

Frequently Asked

What does the name Caius mean?

Caius is the Latin spelling of Gaius, with a possible meaning of rejoice or joy; its exact etymology is debated.

How do you pronounce Caius?

It is said KAY-us — two syllables, stress on the first.

Was Julius Caesar named Caius?

Yes, Julius Caesar's full name was Gaius Julius Caesar; Caius is the alternate spelling of the same Roman given name.

Is Caius from Twilight?

Yes, Caius is also the name of a Volturi vampire in the Twilight series, which contributed to its modern recognition.