Ciao is an informal salutation in the Italian language that is used for both "hello" and "goodbye". Originally from the Venetian language, it has entered the vocabulary of English and of many other languages around the world. Its dual meaning of "hello" and "goodbye" makes it similar to shalom in Hebrew, salaam in Arabic, annyeong in Korean, aloha in Hawaiian, Drud (Bedrud) in Persian, and chào in Vietnamese (the latter is a false cognate; the two words are not linguistically related despite sounding similar to each other).

Source: Wikipedia