sjó

Sjö is the Swedish word for a natural inland body of standing freshwater that is large enough to be considered a lake, as opposed to a pond or stream. In everyday language and in geographic names, sjö denotes such bodies of water within Sweden and, in some contexts, in neighboring regions.

The term is of North Germanic origin and has cognates in related languages, such as Norwegian sjø and Danish sø. In Swedish, sjö specifically refers to inland lakes, while other languages sometimes use analogous terms for larger bodies of saltwater.

Grammatically, sjö is an en-word. The indefinite singular is en sjö; the definite singular is sjön; the plural is sjöar; the definite plural is sjöarna. The word is widely used in place names and in references to bodies of water, including well-known lakes such as Vänern and Vättern, which are commonly referred to as sjöar.

Most Swedish lakes are of glacial origin, formed during the last Ice Age. They vary in depth, water clarity, nutrient status, and, in some regions, salinity. They are part of river basins and undergo seasonal turnover in which water layers mix.

Swedish lakes are central to outdoor life and culture, influencing settlement patterns, recreation, and landscape identity. The word sjö appears in many toponyms and surnames, reflecting the importance of lakes in the Swedish landscape.