In geography a sound or seaway is a large sea or ocean inlet larger than a bay, deeper than a bight, and wider than a fjord; or it may be defined as a narrow sea or ocean channel between two bodies of land (see also strait).

Wikipedia: Sound (geography)

You know that bit of apocrypha that the Eskimos have a hundred words for “snow”? In the Pacific Northwest, we have a hundred words for those bits of water that wash up on our coast.