Décades

Décades are ten-year periods used as a basic unit for organizing time in history, culture, and analysis. In modern usage, decades are typically anchored to calendar years, so the 1980s means the years 1980 through 1989, and the 1990s means 1990 through 1999. The plural form décades is standard in French, and the term is also used in English when discussing multiple ten-year intervals.

In historical and cultural contexts, decades help describe trends and changes that unfold over a relatively long but identifiable span. They commonly frame discussions of fashion, music, technology, politics, and social life. Notable examples include the Roaring Twenties, the Swinging Sixties, or the digital decade associated with the 2010s. Decades provide a shorthand for comparing eras and for tracking the pace of transformation across time.

There are conventions and ambiguities regarding boundaries. The most widespread convention equates a decade with the years ending in 0 through 9 (1980–1989 for the 1980s). However, some uses refer to decades in terms of the year ranges beginning at a decade boundary that some people consider to start at 1 (so 1981–1990, for example). In statistical and scientific contexts, decades may also be defined as fixed ten-year blocks that do not rely on cultural label assignments.

Etymology and language notes: the concept is rooted in the idea of ten, from Latin decas and Greek deka. In French, décade or décennie denotes a ten-year period, with décades as the plural form.

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