the.com/high seas

means The open ocean waters beyond any nation's territorial control, where no single country's laws apply.

from "High" here preserves an old sense of the word meaning open, main, or principal — not elevation, but the chief or full extent of something, as in "high road." The phrase surfaces in maritime and legal English for waters beyond the reach of coastal jurisdiction, running alongside the older term "high seas" / "main sea," the latter surviving today in "the main" as poetic shorthand for the open ocean. The legal concept hardened over centuries of dispute about who, if anyone, can own the sea — a debate that produced the modern law of the sea rather than a single tidy coinage.