Ciao (pronounced “chaow” /tʃao/) is one of those amazing, universal italian words that everyone uses - even people who don’t speak italian! In fact, I would suggest that it is probably the best known Italian greeting in the world.  You can often hear English language speakers around the world using ”ciao” instead of “goodbye” in informal talk.

Ciao is an informal form used at any time of the day, both when you meet and when you leave somebody (it means “hello” as well as “goodbye”). Because it is an informal greeting form, make sure that you only use it it situations where you would use the tu form!  Don’t use it in formal situations (the Lei form).

The origins of the word ‘ciao’ are really interesting, particularly the way that the word has evolved from its medieval roots into its contemporary form.

The word was originally derived from the Venetian word for “slave”, s-ciào ['stʃao] or s-ciàvo, from the medieval Latin sclavus. The Venetian phrase s-ciào vostro or s-ciào su literally meant “I am your slave”; it wasn’t applied literally,but rather as a promise of goodwill and assistance amongst friends (such as “if you ever need my help, I will serve you”). 

Interestingly, the greeting is also cognate to the the Italian schiavo (“your (obedient) servant”), which also originates from the Latin sclavus.

As a bit of background, the institution of slavery existed in medieval Venice, with Slavs often enslaved during the early period, hence the semantic Latin association with sclavus.   Slaves in medieval Venice held a status similar to that of servants, which helps to explain why the Ventians would offer themselves, in greeting, as “your slave” with the obvious intent being a desire to “serve”.

After hundreds of years of common usage , the greeting eventually shortened to ciào [tʃao], lost all its servile connotations and was accepted as  an informal greeting by all speakers, regardless of their social standing.    Ultimately, the Venetian ciào morphed into the Italian language, with the spelling ciao, during the giddy days of the Venetian Republic; since then it spread across Europe and then in the late 19th and early 20th century, to the Americas and then throughout the world, largely by way of Italian immigrants.

A similar development took place with servus, the Classical Latin word for “slave,” in southern Germany, Austria, Hungary, and Poland, where servus is used as a casual greeting like ciao.

Another couple of interesting points - the word s-ciào is still used in Venetian and in Lombardian as an exclamation of resignation:

“Oh, va be’, s-ciào” (”Oh, well, never mind!”)

Also, a well-known Milanese proverb says:

“Se gh’inn gh’inn, se gh’inn no s-ciào” (”If there is [money], there is; if there isn’t, no problem”)

Ernest Hemingway’s novel A Farewell to Arms (1929), which is set in northern Italy during World War I, is generally credited with bringing the word into the English language for the first time.