noun
1 - "Hello!" or an equivalent greeting.
verb
1 - To greet with "hello".
interjection
1 - A greeting (salutation) said when meeting someone or acknowledging someone’s arrival or presence.
2 - A greeting used when answering the telephone.
3 - A call for response if it is not clear if anyone is present or listening, or if a telephone conversation may have been disconnected.
4 - Used sarcastically to imply that the person addressed or referred to has done something the speaker or writer considers to be foolish.
5 - An expression of puzzlement or discovery.
