Hello (interjection)

1. A greeting or expression of goodwill.
2. A telephone call.

Origin:

Mid-19th century alteration of earlier hallo, hollo, which were variant forms of holla, yell, shout, of imitative origin.

Examples:

1. Hello, how are you today?
2. She answered the phone with a cheerful hello.
3. I said hello, but no one answered.
4. The children all shouted hello as they ran past.
5. Hello, is this the right way to the station?