Ciao and Good-bye

Ciao noun - An acknowledgment that can be used to say hello or goodbye (aloha is Hawaiian and ciao is Italian).

Good-bye and ciao are semantically related In some cases you can use "Good-bye" instead a noun "Ciao".

Good-bye noun - An expression of good wishes at parting.

Ciao and good-bye are semantically related in exclamation topic. Sometimes you can use "Ciao" instead a noun phrase "Good-bye".