A New Decade Has Indeed Begun - And Another Begins Next Year

I've seen a number of case where someone has talked about the new decade beginning, and someone jumps in to "correct" them, informing them that, no, the new decade does not actually begin until 2021. Here's an exploration of these matters.

Definition of the Word Decade

Our word decade comes to us from the Latin word decas (genitive decadis), meaning "a set of ten." The Romans had borrowed this useful word from the Greek δεκάς. Latin did already have a word for a span of ten years, decennium.

Even today, the word decade is used, for instance, to refer to 10 Hail Marys on the Rosary, so it isn't yet completely locked into meaning just 10 years, let alone when those 10 years would start or stop.

Decades Beginning on the "Ones"

The belief that decades actually begin only on the "ones" (i.e., 2001, 2001, 2021, etc.) is founded on the quite true principal that, since the Anno Domini (AD) system we use for years began with year 1, decades end on the tens and new decades begin on the ones. 

The AD year reckoning was given to us by a 6th century monk St. Dionysius Exiguus. (He was canonized a Saint by the Romanian Orthodox Church only in 2008.)

He did the best job he could, with the information he had, to determine the year Jesus was born, but we think now that he was off by about 4 years, so Jesus may actually have been born in 4 BC. 

At any rate, there is no year 0 in the AD system. As a result, the end of the first decade of AD was year 10. The second decade of the AD system was AD 11-20. Leading all the way to a new decade in the AD system beginning in the year 2021, not 2020.

Decades Beginning at Other Meaningful Markers

Despite what I describe above, the English word decade is used more freely than just to describe decades of the AD system of years. For instance, it is possible to talk about the first decade of my life. 

I was born in 1966. The first decade of my life ended on my 10th birthday, 1976. And let me tell you, I still remember all of the bicentennial excitement of that time. We were just two weeks or so away from July 4, 1976, the 200th anniversary of the signing of the Declaration of Independence. 

And it is worth noting, just as it is possible to talk about decades of the AD system, we also talk about centuries. The 1st century AD are the years 1-100. The 2nd century are the years 101-200, and so on. But yet that doesn't mean we can't talk about what happened in the first century of US history.

Conclusion

Did a new decade begin on January 1, 2020? 

Yes, it will be that decade we once again call "The Twenties." Just as we can talk about that Golden Age of Music known as the 80's, and that tumultuous time of history known as the 60's, the 20's were, in the 20th century, and will be again in the 21st, a decade of time--a period of ten years.

May the 20's (2020-2029) which began today, and may also the 203rd decade of Anno Domini (2021-2030), which will begin on January 1st, 2021, bring you peace, good health, strength, prosperity, and length of days.