What is a decade?
A decade is a period of 10 years. The word comes from the Greek dekas, meaning a group of ten. Decades are often named by their tens digit, such as the 1990s or the 2020s.
In everyday use, people usually count decades from a year ending in 0 to one ending in 9. For example, the 2010s ran from 2010 to 2019, and the 2020s from 2020 to 2029. Decades are often linked with cultural styles, such as the music, fashion and technology of the 1980s or 1990s.
Some people argue that decades should start with years ending in 1, such as 2021 to 2030, because there was no year zero in the calendar, which jumps from 1 BC to AD 1. This debate is more common for centuries and millennia. For decades, the 0-to-9 system is almost universally used.
Related words
A period of 10 days is sometimes called a decade too, mainly in older or specialized writing. Other time words include a biennium, two years, a quinquennium, five years, a score, twenty years, a century, 100 years, and a millennium, 1,000 years.
Did You Know?
The French Revolutionary calendar replaced the seven-day week with a 10-day week called a décade between 1793 and 1805.