décennies

Décennies is the plural of décennie, a unit of time equal to ten years. In French, it designates a ten-year period and is used to discuss historical, economic, or social trends over that span. The term can refer to a specific ten-year interval, such as a named decade, or to ten-year blocks in general.

Etymology and scope: décennie comes from Latin decennium, meaning a period of ten years, via Old French. The plural décennies is used when speaking of multiple ten-year periods or when referring to the concept of ten-year spans collectively. It is common in historical writing and in discussions of long-term change to speak of “les dernières décennies” or “deux décennies de croissance.”

Usage and nuances: Décennies are not strictly aligned with calendar decades, though they can be anchored to them in everyday language (for example, la décennie des années 1980 or la décennie 2010). In scholarly writing, décennies may cover ten-year blocks that begin at any year, depending on the analytic framework. The plural décennies often conveys a sense of comparison or progression across multiple ten-year periods, as in the phrases “depuis deux décennies” or “des décennies de progrès et de défis.”

Relation to other terms: The singular décennie denotes a single ten-year span, while the more common everyday alternative for naming a period is “les années” followed by the calendar digits (par exemple, les années 1990). In translation, décennie corresponds to decade or decades in English, depending on context.

See also: décade (less common, used similarly but with nuanced emphasis in some contexts); années; histoire par périodes.