How about that ten years?

What is a decade?  Why, of course, it's 10 years. That's correct!   Any period of 10 years.   From a December to a January (98 months) or from a January to a December (120 months) or any combination, as long as the years are 10 as a group.

The word decade is from the Greek dekas.  This is perhaps interesting, as the other year group words (lustrum, century and millennium) are from Latin.  The same concept applies to them also though, simply the time-frame itself changes.


So since any group of ten years is a decade, there are a number of ways to use it that are valid, depending upon the context of the discussion.  Ordinal, cardinal, referential, other; it's 10 years all the same   I'll give some examples of each and we'll be done with it all.


1782-1791   The last decade of Mozart's life.
2002-2011   A decade ending this year.
975-984  A decade that ended in 984. 

1950-1959   The fifties, the nineteen-fifties, the 50s.
2000-2009   The zeros, the twenty-zeros, the 00s.  Zero, null, double-ought.

1-10  The 1st decade.
1901-1910   The 191st decade.
2011-2020  The 202nd decade.


The ten years in the first millennium:ending in 00: 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000.     The even numbered ten years from 2004 to 2012.   The last decade of what we call B.C.,  10 to 1.