sekä

Sekä is a Finnish coordinating conjunction meaning "and" or "as well as." It connects two or more elements—such as nouns, adjectives, phrases, or clauses—and emphasizes that all listed items are included. Compared with the everyday ja, sekä is more formal and common in written Finnish, official discourse, and literary style.

The principal construction to express "both … and …" is "sekä A että B." Here sekä introduces the first element and että introduces the second: for example, "Sekä opettajat että oppilaat osallistuivat tilaisuuteen." Adjectives and verbs can be joined in the same way: "sekä nopea että tarkka tiedonvälitys on tärkeää." Another common form is "A sekä B," which also means "A as well as B" (for example: "Opettajat sekä oppilaat osallistuvat").

Sekä is versatile and can introduce multiple items in longer lists, though in practice it most often appears in two-item constructions. In contemporary Finnish, sekä remains a standard option in formal writing, while casual speech may simply use ja. Its use helps to convey equality or inclusivity among the listed elements and is a hallmark of careful, precise expression in Finnish.