Meaning of “decade” - Learner’s Dictionary

decade

noun [ C ] us uk /ˈdekeɪd/
This decade has seen huge technological advances.Crime in the city has increased during the past decade.The firm will invest £1 billion over the next decade.For over a decade I lived with this knowledge.The basic idea has been around for decades.

B2 a period of ten years

(Definition of “decade” from the Cambridge Learner’s Dictionary © Cambridge University Press)