Caia is the feminine form of the Roman name Gaius, also spelled Caius, whose meaning is uncertain but is traditionally linked to the Latin gaudere, "to rejoice". In the Roman wedding formula the bride declared "where you are Gaius, I am Gaia", which made the name a symbol of marriage. In the United States Caia has stayed between number 2,100 and 2,700 for a decade, reaching number 2,138 in 2024 and number 2,696 in 2025, with 64 births.