1000s

noun[plural only]3

1. •
   The decade from 1000 to 1009.
2. •
   The century from 1000 to 1099.
3. •
   (rare) The millennium from 1000 to 1999.

   • What Roman numeral might you find in the cornerstone of a building built in the year 2000? MM – the mark of the new millennium, a move from the 1000s to the 2000s. — 1999