Caius

boyLatinChristian

Caius is a boy name of Latin origin, meaning “Possibly 'rejoice'; meaning uncertain”.

MeaningPossibly 'rejoice'; meaning uncertain
GenderBoy
OriginLatin
PronunciationKY-us
TraditionModern & Classic, Christian
Used inUnited Kingdom, United States, Brazil

Meaning and origin of Caius

Caius is a spelling of the Roman first name Gaius, borne by Julius Caesar (Gaius Julius Caesar) and many other Romans. Its origin is not certain; it is often linked to Latin gaudere, 'to rejoice', though that may be folk etymology. A Gaius appears in the New Testament as the recipient of the Third Letter of John. In Britain Caius is also known through Gonville and Caius College, Cambridge, pronounced 'keys'.

Is Caius a religious name?

Caius is an ancient Roman name; in its form Gaius it appears in the New Testament, and several early Christians, including a Pope Caius, bore it.

How popular is Caius?

Rare but rising among parents drawn to classical names.

Gifts with the name Caius

As an Amazon Associate we earn from qualifying purchases. We may earn a small commission from these links, at no extra cost to you.

Spellings and variants of Caius

GaiusKaiCaioKaius

Names similar to Caius

More boy names

Frequently asked questions

What does the name Caius mean?

Caius means 'Possibly 'rejoice'; meaning uncertain'. It is of Latin origin.

Does Caius have a religious meaning?

Caius is an ancient Roman name; in its form Gaius it appears in the New Testament, and several early Christians, including a Pope Caius, bore it.

How do you pronounce Caius?

Caius is pronounced KY-us.

Is Caius a boy or girl name?

Caius is usually a boy name.

Updated October 2026. Spotted a mistake? Tell us.