Updated June 9, 2019 Find Baby Names Boy name origins & meanings Latin : Rejoice; variation of GaiusWelsh, German : Rejoicer; fort; joyful Boy name variations Caius Caius + 9% this year Masculine Rare READ MORE DETAILS Cai Cai + 18% this year Masculine Rare READ MORE DETAILS Caio Caio - 6% this year Masculine Rare READ MORE DETAILS Kay Kay + 10% this year Neutral Rare READ MORE DETAILS Keye Keye 0 % this year Masculine Rare READ MORE DETAILS Keyes Keyes 0 % this year Masculine Rare READ MORE DETAILS Keys Keys 0 % this year Masculine Rare READ MORE DETAILS Cais Cais 0 % this year Masculine Rare READ MORE DETAILS Kai Kai + 14% this year Neutral Common READ MORE DETAILS Kaysie Kaysie - 13% this year Neutral Rare READ MORE DETAILS Keh Keh 0 % this year Masculine Rare READ MORE DETAILS MacKay MacKay 0 % this year Masculine Rare READ MORE DETAILS Family name origins & meanings English : variant spelling of Kay 4 and 5.