10 decades make a century, while 100 decades make a millennium.A decade is any 10 year period: There are different ways to refer to different groupings of ten years. As January 1, 2020, approaches, everyone is reflecting about the past decade and the new one that awaits. #10YearChallenges are all over social media. So pick your frame of reference. “Since the first year on record was 1, then 10 ended that decade with 11 starting the next one.

Unanswered I’ve heard some people say a new decade starts when the number changes (i.e., 2000, 2010, 2020, etc), but I’ve heard other people say a decade starts when it’s year 1 (2001, 2011, 2021, etc) because a decade is year 1-10. If you want to play little gotcha-games, you can say, “Oh, no, the first decade of the third millennium isn’t over until the end of 2010!” Both are true. If you want to refer to a decade such as we usually think of them in our culture, the ’20s, ’40s, ’70s, etc., then 2010 starts a new decade. Does the next decade start in 2020 or 2021? The first decade of the 21st century, therefore, consists of the years 2001 through 2010, no matter how many “Decade in Review” essays, roundups, recaps, and slideshows you’re being bombarded with as 2009 comes to an end. That said, those who would care to call it a decade on Dec. 31 have plenty of ammunition, if not reason, on their side. The first decade of the 1st century ran from Year 1 through Year 10. "Best of the decade" lists are everywhere. Inquirer Morning Newsletter Get the news you need to start your day The decade of the 2020’s starts January 1, 2020,” argues a Team 0 camper in New York. A decade is a period of 10 years.

For example, the period from 2001 to 2010 can be described as the 1st decade of the 21st century. The word is derived (via French and Latin) from the Ancient Greek: ... (20s), starts with the 21st year of life (during which one is referred to as being 20) and ends at the end of the 30th year of life on their 30th birthday; subsequent decades of life are described in a similar way by reference to the tens digit of their age. The lack of a year zero means the first A.D. decade started at year 1 and ran until the end of year 10; the second decade started on year 11. A decade (pronounce: DEK-aid) is a period of 10 years.The word comes from the Ancient Greek word for ten: "deka".