The Difference Between A Sound And A Strait
Different regions sometimes use different words to describe similar natural features, and bodies of water are no exception. Mapmakers and explorers have historically applied varied names to coastal waterways based on local traditions and physical traits. This can create confusion when distinguishing a sound, such as Puget Sound, from a strait, such as the Strait of Juan de Fuca. Although these waterways can share similar characteristics, straits generally have a more consistent geographic definition, whereas the term "sound" can refer to several types of coastal features depending on the region and naming conventions.
Straightening Out Straits
Straits have a relatively consistent definition. A strait is a naturally formed, narrow waterway that connects two larger bodies of water, such as seas or ocean basins. Straits can form through several geological processes, including tectonic activity, erosion, and rising sea levels that flood low-lying areas between landmasses. Unlike canals, which are artificially constructed waterways, straits occur naturally. Because they connect larger bodies of water, they often become major routes for international trade and transportation. For instance, the Strait of Gibraltar connects the Mediterranean Sea to the Atlantic Ocean. It marked a key boundary of the ancient Mediterranean world, and control over the passage offered significant strategic advantages. Some straits have global economic importance, such as the Strait of Hormuz. This narrow waterway connects the Persian Gulf to the Gulf of Oman, which opens into the Arabian Sea, and serves as one of the world's most important petroleum shipping routes.
A Regional Sound
Sounds have a less consistent definition, and the term can describe several types of coastal waterways. Sounds may be broad inlets, passages between islands and the mainland, or waterways connecting larger bodies of water. One example is Long Island Sound, which lies between Long Island and the mainland shores of New York and Connecticut. However, this arrangement is not universal. In some regions, particularly northern Europe, the term "sound" is also used for narrow passages that meet the geographic definition of a strait. Elsewhere, sounds can include broad coastal inlets or partially enclosed areas of seawater. These variations reflect historical naming practices rather than a universally applied classification. As a result, identifying a waterway as a sound does not necessarily reveal its precise physical characteristics.
Confounding Fjords
Some waterways called sounds are actually other landforms, including fjords. In New Zealand's Fiordland region, most of the fjords are named sounds. A fjord is a long, narrow, and often deep coastal inlet bordered by steep slopes or mountains. Fjords form when glaciers carve deep valleys that are subsequently flooded by the sea. Milford Sound and Doubtful Sound are examples of these glacially formed waterways, while others in the region, such as Preservation Inlet, go by different names. Although Milford Sound is called a sound, its geological formation identifies it as a fjord.
Elsewhere on New Zealand's South Island, the Marlborough Sounds provide a useful contrast. Unlike the glacially carved fjords of Fiordland, the Marlborough Sounds developed when rising sea levels flooded a network of river valleys. The resulting coastline contains numerous inlets, bays, and waterways extending between hills and peninsulas. Northern Europe provides another example of overlapping terminology, as some narrow waterways connecting larger bodies of water are called sounds even though they also fit the definition of straits. These examples demonstrate why the names appearing on maps do not always identify a waterway's geological origins or geographic classification.
Looking Past The Label
Distinguishing between a sound and a strait can be difficult because the terms sometimes describe overlapping geographic features. Straits are generally narrow natural passages connecting larger bodies of water, while sounds may be broader coastal inlets, partially enclosed waterways, or passages between landmasses. Neither type is defined by a single geological formation process. Regional naming traditions also contribute to the confusion, as demonstrated by New Zealand's fjords and northern Europe's sounds. Ultimately, understanding a waterway's geography and formation provides a more reliable explanation of its characteristics than its name alone.
