You think you know what it means. It’s a pretty standard word, even in English. Your Starbucks-sipping, wannabe Italian friends use it all the time when they’re bidding you “adieu”. It’s practically a no-brainer. But in Italy, “ciao” is used for both “bye” and “hi”, and can often be doubled up for a cute “ciao ciao”, especially when parting ways, or drawn out to a “ciaooooo!” when you’re especially pleased to see someone.
But have you ever noticed that while on the telefono (and they always are!) Italians just don’t want to hang up? Their reciprocal “ciaos” and “arrivedercis” go on forever at the end of a conversation, usually lessening in volume until one of the conversation partners finally hangs up (or dies from not having taken a breath in so long).