Hi (interjection)

1. Used as a greeting or to attract attention.
2. Used as an expression of enthusiasm or excitement.
3. Used to introduce a phone call.
4. Used to express recognition or greeting.
5. Used to express a welcome or greeting.

Origin:

Late 19th century: alteration of earlier high.

Examples:

1. Hi, how are you?
2. Hi, it's good to see you!
3. Hi, can I help you?
4. Hi, what's up?
5. Hi, I'm calling to see how you are.
6. Hi, welcome to the store.