What is the name of the first decade in a century?
When you wanted to state that something belongs to a previous era's fashion at the turn of the century you could say so 90s or so 20th century.
Now when you want to say that something belongs in the 200xs what would you say?
(So zeros or so aughts just doesn't sound right.)
Edit: This is not a duplicate of What is the name of the first decade in a century?