A new decade?

Does 2020 start a new decade, or does the decade actually start next year? I answer with a firm “yes.”

It depends on if you’re using ordinal numbers or cardinal numbers. 2020 is the last year of the second decade of the twenty-first century (and of the third millennium) but it’s the first year of the 2020s. Similarly, 2000 was the last year of the twentieth century and of the second millennium, but the first of the 2000s.

Of course, you could always just appeal to authority.