'Hello' definitions:

Definition of 'hello'

From: WordNet
noun
An expression of greeting; "every morning they exchanged polite hellos" [syn: hello, hullo, hi, howdy, how- do-you-do]

Definition of 'Hello'

From: GCIDE
  • Hello \Hel*lo"\, interj. & n. An exclamation used as a greeting, to call attention, as an exclamation of surprise, or to encourage one. This variant of Halloo and Holloo has become the dominant form. In the United States, it is the most common greeting used in answering a telephone. [1913 Webster +PJC]

Synonyms of 'hello'

From: Moby Thesaurus