Ciao

salutation of Italian origin

The word "ciao" is a greeting in Italian. It is used for both "hello" and "goodbye". It is less formal than other greetings in Italian, such as buongiorno or salve.

English Wiktionary
English Wiktionary
The English Wiktionary has a dictionary definition (meanings of a word) for: ciao

The word originally comes from the Venetian language. It is also sometimes used by English speakers and speakers of other languages around the world. Other words that mean both "hello" and "goodbye" are shalom in Hebrew, salaam in Arabic, annyeong in Korean, and aloha in Hawaiian. In Vietnamese, the word chào also means "hello" or "goodbye". It sounds similar, but is not related to the Italian word.