Boy name · Latin
Caio
“to rejoice, glad”
Vibes
Common nicknames
Short-forms and diminutives parents often use for Caio.
Explore Caio further
Similar-feel alternatives, or middle-name candidates that pair well with Caio — both ranked by the same scoring system (vibe overlap, syllable rhythm, origin compatibility).
About the name
Caio is the Italian and Portuguese form of Gaius, the most common of all Roman first names — so common that legal formulas used Gaius and Gaia the way English uses John Doe. It is usually derived from gaudere, to rejoice.
It is a top-tier boys' name in Brazil and is separately a Welsh name, from the Roman occupation, pronounced KY-oh in both. It has never ranked in the US, where the spelling reads as unfamiliar despite being two easy syllables.
Cai stands alone as a Welsh name. Two syllables want two or three (Caio Mateus, Caio Rafael). On our vibe map it is Modern Minimalist, with Cultural Fusion behind a real aesthetic primary.
More Latin names
Caio sits in our Latin set — these share its roots.
All Latin names →Caio — common questions
Is Caio a boy or girl name?
Caio is traditionally a boy name of Latin origin.
What does the name Caio mean?
Caio means “to rejoice, glad” of Latin origin. Caio is the Italian and Portuguese form of Gaius, the most common of all Roman first names — so common that legal formulas used Gaius and Gaia the way English uses John Doe. It is usually derived from gaudere, to rejoice.
Where does the name Caio come from?
Caio is Latin in origin. It is a top-tier boys' name in Brazil and is separately a Welsh name, from the Roman occupation, pronounced KY-oh in both. It has never ranked in the US, where the spelling reads as unfamiliar despite being two easy syllables.
What are common nicknames for Caio?
Cai — the short-forms parents most often use for Caio.
How popular is Caio?
Caio did not make the top 1,000 boys' names in US Social Security Administration data for 2025, which makes it genuinely rare in the US.
Bring the name into the room
A couple of nice things named Caio you might want for the nursery.