A demi-decade is a period of time considered to be equivalent to half a decade, roughly five years. Prototypically this milestone falls in years which end in the number 5, since the most common perception of a decade is the run of years ending in digits 0 to 9.

What is a 5 year period called?

1 : consisting of or lasting for five years. 2 : occurring or being done every five years.

What is every 10 years called?

1 : consisting of or lasting for 10 years. 2 : occurring or being done every 10 years the decennial census. Other Words from decennial More Example Sentences Learn More About decennial.