Underwater vs. under water

Underwater is one word when it is an adjective preceding the noun it modifies. When it follows what it modifies, it is usually one word (e.g., his head was underwater), but underwater is still a fairly new compound—only about a century old—and is not 100% accepted, so some publishers still use under water when it follows what it modifies (e.g., his head was under water). This practice is becoming less common, though, and you are safe with the one-word spelling for all uses of the word.


Their underwater beauty and sea life draw thousands of people to the waters every year. [Globe and Mail]

Millions of Americans remain underwater on mortgage loans. [New York Times]

High-quality rum, though, such as the local Seven Fathoms, aged underwater in oak barrels, is best savoured slowly. [Guardian]

1 thought on “Underwater vs. under water”

  1. Yet another example, IMO, of compound words taken to an extreme that undermines their meaning, much like “backyard.” Even the NYT and AP now accept “backyard” as a noun. You know when “backyard” will be how I refer, in writing, to the lot behind my house? When it is also universally agreed that the other one is my “frontyard.” In other words: Never!

    Compound words as after-the-noun modifiers are less a function of any profound change in grammatical theory than a result of laziness – on the part of editors, writers, and readers.


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