What Italian word means both 'Hello' and 'Goodbye'?
Ciao can be heard at the beginning and the end of an interaction so in that sense it can be interpreted as meaning both "Hello" and "Goodbye."
Specifically, the Italian word is a greeting that means "hello, hi." But it may be heard at both the start and the finish of conversations. The pronunciation is "tchow."*
*The sound is similar to that in the English noun "chow."