Sea, ocean, or open water
Kaien is a modern name often used as a variant of the Hawaiian name Kai, meaning sea. In Japanese contexts, it can be formed from kanji meaning 'ocean' and 'salt' or 'boundary,' though its usage in the US is primarily as a creative phonetic variation.
About 10 boys were named Kaien in 2025.
US births per 5-year period, 1990–present (SSA data).
