What is Madonna's last name?

What is Madonna's last name?

Some people only need one name to get the point across. Among this echelon are some of the greatest within their discipline: Pelé, Slash, Cher, Bono, and Flea, to name a few.

But then there's Madonna, who seems to hover above nearly all other one-namers in pop-culture history. And maybe all of history (sorry, Voltaire).

But she does have a last name, and in fact, she's never changed her name. What's Madonna's surname?

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