Definition, synonyms and related words
plural of decade.
"The old building had seen three decades of rain and snow before it finally collapsed."
In plain English: Decades are groups of twenty years used to talk about time periods.
"They have known each other for decades."
Usage: Use "decades" to refer to two or more ten-year periods, such as when discussing changes that occurred over the last few decades. Avoid using it to mean years in general, as that requires the singular word "years."
Derived from the Greek deka meaning ten, this term originally referred to a period of ten years. It entered English via Latin and French in the mid-16th century with that same numerical designation.