There are ten (10) years in a decade. The word decade is derived from an ancient Greek word δεκάς, which translates dekas in French/Latin language, meaning a group of ten.
The decade is often used to distinguish the times of people’s lives such as the 60’s decade which means 1960 to 1969 or the ‘80s. which are the years 1980 to 1989.
By using decade in this manner, people will find it easy to say for example, that a certain fashion is from this decade when they are not sure the exact year of it. The word decade can also mean a span of ten years, for example, she had built herself a house in a decade.