Tiår

Tiår is a time unit used in Swedish and Norwegian to denote a period of ten years, i.e., a decade. It is used in historical writing, statistics, economics, and cultural analysis to describe trends or events across ten-year blocks. The word is formed from ti (ten) and år (year) and is often written as one word in Scandinavian orthography, though variations can occur in different texts or languages.

A tiår can refer to a specific calendar decade, such as the tiår 1980–1989, or to any ten-year span defined relative to a starting point chosen by the writer. In scholarly writing, the synonym decennium is common, especially in formal statistics and historiography. In everyday language, tiår is frequently encountered in discussions of anniversaries (tiårsjubileum) and in long-term planning or projections. Overall, tiår serves as a convenient and neutral unit for organizing time, data, and events by decades.