Definitions

1. interjection

an expression used to greet someone or to attract attention

“She said hello to the stranger on the street.”

2. verb

to greet or address someone with a friendly greeting

“Please hello the guests as they arrive.”

3. noun

a greeting or a salutation

“The hello was loud and clear across the room.”

4. adverb

used to indicate a greeting or to express a friendly attitude

“She helloed the teacher warmly.”