Interesting fact of the day: The first recorded use of the word "Hello" was in 1866, and the first published use in 1867. At the time it was not used as a greeting but rather as a proclamation of suprised like "Well well, hello, what do we have here".

It only came to be used as a greeting because it was popularized as such by Alexander Bell when he encouraged people to use it as a greeting when picking up the phone due to the open-line nature of phones at the time.