Kaio is of Japanese origin, meaning 'the sea'. It's composed of two kanji characters, '海' (umi) meaning 'sea', and '王' (ō) meaning 'king'. This name gained popularity globally following the success of professional wrestler Kaio-King during the 1980s and 1990s. It has since been adopted by various cultures, notably in Brazil where it's seen a significant increase in usage.
The name Kaio experienced a significant rise in popularity from the late 1990s to the mid-2010s, with a peak of 23 births in 2008 and another peak of 26 births in 2023. However, there were periods of decreased popularity, such as in the early 1990s (5 births in 1993) and from 2015 onwards (9 births in 2015, 15 births in 2016). Overall, there were a total of 381 Kaio births recorded between 1993 and 2023.