Meaning: The second decade of any century. Example: 2011 to 2020.
Usage: The Khilafat movement was a product of the late tenties.
Root: Since the years in question lie between TEN and tweNTY. it might make eminent sense to club the two and form a new word called TENTIES. So a century can be neatly summed up as noughties, tenties, twenties, thirties, forties, fifties, sixties, seventies, eighties and nineties.