So what is the difference between a loch and a lake? Well, the main distinction is where they are located. Lochs can be found in Scotland and Ireland whilst lakes are found elsewhere in the world. This is because the word 'loch' comes from the Gaelic languages which were historically used in these parts of Britain.

The primary difference between a loch and a lake is geographical and linguistic rather than biological. In Scotland and parts of Ireland (where they use the term "lough"), inland bodies of water are almost exclusively referred to as lochs, a word derived from Scottish Gaelic. Conversely, "lake" is the standard English term used throughout the rest of the world. While most lochs are freshwater bodies similar to lakes, the term "loch" is also applied to sea inlets—long, narrow arms of the sea that are often glacially formed, known as sea lochs (similar to fjords). Interestingly, Scotland has only one major natural body of water officially called a "lake": the Lake of Menteith, which received its name due to a 19th-century linguistic misunderstanding. For all practical purposes, if you were to see Loch Lomond in any other country, you would simply call it a lake, but in the Highlands, the cultural and historical weight of the word "loch" is a defining part of the landscape.