How Long is a Decade? Everything you need to know.

Whenever you heard or read any history or past political events, you may have come across the word “Decade”. In this article you will understand “how long is a decade?” and everything about the decade such as the history of decade, exactly how long is the decade? Terminologies other than decades, Important events in the past decades.

Go through this article thoroughly. I am sure, there will not be any confusion regarding decade terminology in your life.

Origin of the word “Decade”?

In ancient Greek “dekas” word was used to identify a group of 10 entities. Later Romans started using the word Decade which was derived from “dekas” via Latin and French.

Exactly how long is a Decade?

A decade is a time span of 10 years. Generally, you can count from any year. There is no specific defined rule, but make sure the time span must be of 10 years. There are different theories and assumptions regarding the start and end year of the decade. Continue reading this article to understand the start and end year of a decade.

How to identify 20, 30, 40, ……. years’ time span?

There are no specific terms to defines 20, 30, 40, … years of time span. But there are some terminologies that are derived from Latin as explained in the below table.

Time Span (Years)	In terms of Decade	Latin Name of Time Span
10	1 Decade	Decennial
20	2 Decades	Vicennial
30	3 Decades	Trigentennial
40	4 Decades	Quadragennial
50	5 Decades	Semicentennial
60	6 Decades	Sexagennial
70	7 Decades	Septuagennial
80	8 Decades	Octogintennial
90	9 Decades	Nonagintennial
100	10 Decades	Centennial

What is century and Millennium?

Century:

Century is a period of 100 years or you can say, period of a 10 decades. Currently we are living in a 20^th century. In Latin it is called as a Centennial.

1 Century = 10 Decades = 100 Years

Millennium:

Millennium is a period of 10 Centuries or 1000 years or you can say, period of a 100 decades. In Latin it is called as  a Millennial.

1 Millennium = 10 Centuries = 100 Decades = 1000 Years

Why decade is an important terminology to explain history?

As explained above, a decade is a time span of 10 years. Major events that happened in the past can be easily tracked and remember using a decade instead of the exact year. Some events such as world war 1, world war 2, the cold war, and disturbance in Syria happened over a period of certain years. Their causes and impacts can last for over a period of time. It becomes difficult to track or record the exact dates or years of those events. That is why decade terminology becomes so much important while explaining the major events in history.

When does the decade start? 2020 or 2021?

It’s a really interesting topic, probably you might have wondered this couple of times. Whenever we say decade, first thing comes to our mind is the period of 10 years. But have you ever thought when the decade actually starts? This question is important because logically and calendar wise people have different opinions about it.

Let’s try to understand by taking an example of 90’s decade.

When you say 90’s decade, then which time span comes to your mind? 1990 to 1999 or 1991 to 2000?  Years from 1990 to 1991, contains all the years of 90’s series and years from 1991 to 2000, contains 2000 which does not belong to the 90’s series. So logically years from 1990 to 1999 is a correct timespan. By this logic 0-9 is a decade’s time span.

But when you see a calendar, there is no 0^th year. Years started from 1 to the current year, so 1 to 10 is the correct time span to decide a decade. This way, the years from 1991 to 2000 are called the 90’s decade. So, up to you how you want to take it.

Important events from 19^th century decades to the current decade in world history:

Decade Period	Important Events
1901 – 1910	Airplane invention by wright brothers, Tunguska event
1911 – 1920	World War – 1, Russian revolution
1921 – 1930	Women’s Suffrage in USA, first time women get to vote, Rise of Chinese communism, Kanto earthquake in Japan, Beginning of a Mickey Mouse era. Stock market crash which lead to depression in USA.
1931 – 1940	Rise of Nazis in Germany, Hitler comes to power, persecution of Jews, start of World War – 2 in Poland.
1941 – 1950	World War – 2, Cold war between west and Soviet Union, Independence of India, Assassination of Mahatma Gandhi, Rise of Israel.
1951 – 1960	Discovery of Polio vaccine, Beginning of civil rights movement in USA.
1961 – 1970	Assassination of Martin Luther King, Vietnam War, Soviet Union’s successful space mission.
1971 – 1980	Vietnam War, Jonestown Massacre, Munich Olympics massacre, Watergate scandal in USA.
1981 – 1990	PATCO Strike, Fall of Berlin Wall, End of cold war, Poison gas leak in Bhopal, Stat of video games and 24 hour news channels, evolution of internet.
1991 – 2000	Bombing in Oklahoma City, massacre in Rwanda, Nelson Mandela was released from prison.
2001 – 2010	Death of Steve jobs, Revolution in mobile telecommunication, Financial crisis, Crash of share market.
2011 – 2020	India won the cricket world cup, United Kingdom’s withdrawal from European Union, Black lives matter movement in USA, Outbreak of Corona Virus

Conclusion:

I hope in this article you got to know everything about a decade especially how long is a decade, when the decade actually starts, the history of decade and important events from 19^th century decades. I hope by reading this article you got a clear understanding of all aspects of Decade terminology. Do share your thoughts in the comment section refgarding decade to let others know what you think.

Some interesting FAQs about the decade: