sisè

Sisä is a Finnish word meaning inside or interior. In everyday Finnish it functions mainly as a root that forms a productive prefix, sisä-, which attaches to a wide range of nouns and adjectives to denote internal aspects, locations, or characteristics. As a free-standing word, sisä is relatively rare and is usually encountered in compound terms rather than in isolation. It contrasts with ulko- meaning external or outside.

Common examples of the sisä- prefix in use include sisätila (interior space), sisäilma (indoor air), sisätilat (interior facilities), sisämarkkinat (internal market, as in the European Union context), sisämaa (inland or interior of a country), sisäelimet (internal organs), and sisäpuoli (inner side). The prefix also appears in words describing internal processes or properties, such as sisäjärjestelmä (internal system) or sisäkorva (inner ear). The related adjective sisäinen and the adverb sisäisesti derive from the same root and are used to express internality or inward direction.

Etymologically, sisä is a native Finnic root that has given rise to numerous compounds and derived forms. It is commonly taught as part of vocabulary related to anatomy, architecture, geography, and administration. In linguistic terms, sisä- stands as one of the key productive prefixes for describing spatial relations and internal states, with the antonymous prefix ulko- used for exterior or outward aspects.