Ciao used to mean "I am your slave"

In Venetian, "s-ciào vostro" meant "I am your slave". Nobody meant it literally. It was a polite formula, like signing a letter "your humble servant", and you can still read "schiavo vostro" in the comedies of Carlo Goldoni, the Venetian playwright of the 1700s.

Over time the phrase lost its second word and most of its deference. Ciao became a casual greeting between friends, and around the turn of the 20th century it spread from northern Italy across the country and into the rest of Europe.

Italian emigrants carried it to South America. It became "chau" in Argentina and "tchau" in Brazil, where it usually means only goodbye.

Italy isn't alone here. In Austria, Bavaria and much of Central Europe people greet each other with "servus", Latin for servant.

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