(German) and Scandinavian: pet form of any of various Germanic names beginning with K- or G -. It has been connected with Gerhard and Klaus. It also may alternatively be from Latin Gaius, an ancient Roman personal name (see Caius) or even from Caietanus (see Kajetan), although the latter is primarily a Roman Catholic (South German) name, while Kai is predominantly North German. The reasons for its adoption and recent meteoric rise in popularity in the English-speaking world are unclear. In the United States, it may also in part represent a Hawaiian word meaning ‘the sea’.