decade

American  

[dek-eyd, duh-keyd] / ˈdɛk eɪd, dəˈkeɪd /

noun

1. a period of ten years.

   the three decades from 1776 to 1806.

2. a period of ten years beginning with a year whose last digit is zero.

   the decade of the 1980s.

3. a group, set, or series of ten.

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decade British  

/ dɪˈkeɪd, ˈdɛkeɪd /

noun

1. a period of ten consecutive years

2. a group or series of ten

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Other Word Forms

Derived Forms

• half-decade
  noun
• decadal
  adjective

Etymology

Origin of decade

First recorded in 1425–75; late Middle English, from Middle French, from Late Latin decad-, stem of decas, from Greek dekás “group of ten”; equivalent to deca- + -ade ²

Explanation

She was so nervous to see her high school sweetheart at their reunion: it had been a decade (ten years) since she'd seen him at graduation, and she still got butterflies thinking about him. A decade is a period of ten years. Decade contains dec, which is used in words that have to do with tens. The Marty Paich Dectet was a band with ten players. A decahedron is a shape with ten faces. And the decimal system is based on the number ten.

Example Sentences

Over the past decade, Lozano's group has tested numerous designs under different operating conditions and with a variety of ionic liquid fuels.

From Science Daily • Jun. 10, 2026

Founded a decade ago, OpenAI kicked off the modern AI boom with the release of ChatGPT in 2022.

From Los Angeles Times • Jun. 10, 2026

Almost a decade ago, Nebraska made it easier to recover Medicaid costs.

From MarketWatch • Jun. 10, 2026

It doesn't make sense to destroy that installed base, so existing trucks will remain in service for another decade or two as the old generation gives way to its autonomous successor.

From The Wall Street Journal • Jun. 10, 2026

Isobel racks her brain for the last time she felt under the weather and she can only come up with a head cold she had a decade ago, the winter before she met Marco.

From "The Night Circus" by Erin Morgenstern