decade

The word “decade” means a period of ten years. In plain terms, ten years, or more loosely, any group of ten things.

“Decade” is pronounced DEH-kayd (/ˈdɛkeɪd/ in IPA).

Here is “decade” used in a sentence: “The band has been touring for over a decade.”

“Decade” is a noun.

The word “decade” comes from Old French. From Old French decade, from Greek dekas, "a set of ten," from deka, "ten.".

“Decade” is a fairly common word in modern English, usually learned at around the B2 level.

“Decade” has 2 distinct senses listed in this dictionary. The most common is: a period of ten years.

A decade is exactly ten years. Three decades make thirty years, and ten decades make a century. People often use the word to describe cultural eras, such as "the 1990s" or "the last decade," grouping events, fashions, and trends into memorable ten-year spans that are easy to talk about.

A decade is ten years; a century is one hundred years, or ten decades. Both mark spans of time, but a century is far longer. We might say a style defined a decade, while a great change shaped an entire century. The scale is the key difference between them.

This is debated. Popular usage treats decades as beginning at year zero — the 2020s run from 2020 to 2029. Strictly, since there was no year zero in the calendar, some argue a decade runs from 2021 to 2030. Most people follow the simpler, common convention.

Decade comes from the Greek "deka," meaning ten, reaching English through Latin. That root is why it always refers to a group of ten — in this case ten years. The same "deka" root appears in other counting words, such as decagon, a shape with ten sides.