Dear Word Sommelier: I was just watching The Little Mermaid and I was struck by the song “Under the Sea.” The sea is the water, right? All the creatures are in the water; only the sea bed is under it. So shouldn’t it be “in the sea”? Or is this one of those idiomatic things? If I wanted to write about the beauty of sea life, should I write about the colours in the sea or the colours under the sea?
Oh, prepositions are bedeviling. Which preposition goes with what is one of the least predictable things about any language. But I’m not going to wave this off with “It’s idiomatic” (which might be read as “It’s idiotic, Ma”). In this case you have two usable options, depending on your choice of schema for the sea: as container or voluminous body, or as surface with or without depth: without, like a boardwalk (“under the boardwalk, down by the sea”), or with, like a blanket of snow.
Under the sea uses the “surface” schema; it means below the surface of the sea, and – giving the sense that it’s a surface with depth – usually towards the bottom; the fact that it’s actually in the seawater doesn’t change the “under” relationship to the surface and to all the water on top of whatever is under the sea. Jules Verne’s book 20,000 Leagues Under the Sea is something that often hovers in the mind when one speaks of being under the sea, as does the Beatles’ “I’d like to be under the sea, in an octopus’s garden in the shade.” Another phrase that makes use of the same schema is beneath the sea – or, perhaps more commonly, as in “Octopus’s Garden,” beneath the waves (do remember that waves are more than just a pure surface phenomenon in reality). We must remember, too, the very common word and image underwater (and its counterpart underground).
In the sea, on the other hand, uses the “container” or “voluminous body” schema (that’s two different schemata, not two names for the same one). It presents an image of being in the water, surrounded by it or as part of it or using it as a medium. It can even involve being partly out of the sea (e.g., swimming, which you do not do “on the sea”).
There’s also the question of vantage point. If you’re looking at the colours in the sea, you’re most likely looking at them from outside, perhaps on a boat looking down into it. To see all the colours under the sea, you’d more likely have an undersea perspective yourself – if not in a submarine or scuba diving, then at least snorkeling or in a glass-bottom boat. Also, colours in the sea could imply or at least include the colours of the water itself, which colours under the sea would less likely do – though it might imply the colour of the light coming down through the water.
There’s also the phonaesthetic angle, which is a little fuzzier: under has that depth of sound, that hollow central vowel with the resonant nasal-stop /nd/ and the echo syllabic /r/, just like thunder (and also, of course, blunder, chunder, plunder, and wonder). Anyone who has had their head under water and heard hard things bonking together in the water (even if it’s just your shampoo bottle falling into the tub) will have some sense of that hollow sound. In, on the other hand, has a high front vowel into a simple nasal. It’s short, direct, less resonant, less capable of evocativeness. One might say it’s a jackknife dive to under’s cannonball, but it’s not really amenable to even that much flourish.
In a song like “Under the Sea,” of course, the rhythm is an important part of it. But for other uses, you may also want to consider the sound and the rhythm along with the image. Oh, and less-common usages tend to have a certain dearness compared to more-common ones… and under the sea is and (indications are) has always been somewhat less common than in the sea.
Just as a parting shot, ask yourself whether you would use under the ocean. I suspect most people would find it less idiomatic. Sea, an English word as long as there has been an English, has more native idioms and a greater literary accretion. Ocean is a loan from Greek (via Latin and French, arriving in English in the 13th century) and, like many such, is a little more technical and precise, and a little less flexible.
Thanks to Gael Spivak and several other editorial colleagues for input and inspiration.
Questions for the word sommelier are always welcome!