The term "the high seas" refers to the open sea area beyond the jurisdiction of any state. There are different nouns that can be used as synonyms for this term. For instance, "the open water" is a generic expression that describes the vast expanse of water, including the high seas. Another synonym is "the vast ocean," which conveys the idea of expansiveness and unpredictability of the sea. "The deep blue" is another synonym often used as an adjective to describe the high seas. Furthermore, "the open sea," "the open ocean," and "the high waters" are also synonyms used interchangeably with "the high seas," depending on the context.