The word 海域 is formed by combining the character 海 (hǎi), meaning "sea" or "ocean", with the character 域 (yù), meaning "area" or "region". Together, they create a compound noun where 海 specifies the domain related to the sea, and 域 defines it as a bounded space, resulting in the meaning "maritime area" or "sea region". This formation directly conveys the concept of a specified oceanic zone through the literal sum of its parts.