The traditional Aboriginal name for Melbourne is Naarm in the Woiwurrung language of the Wurundjeri people, the traditional custodians of Melbourne and surrounds. Naarm, meaning scrubland, is connected to the creation narrative of the Birrarung, or Yarra River.
Melbourne, the capital of Victoria, was founded in 1835, in the reign of King William IV, and was named in honour of the Prime Minister of Great Britain, William Lamb, 2nd Viscount Melbourne (of Kilmore). The current population of Melbourne is 5 million people.
The people of the Kulin Nation, a collective of five Aboriginal nations (Wurundjeri, Boonwurrung, Wathaurrung, Daungwurrung and Dja DjaWrung) inhabited the area for an estimated 40,000 years and, prior to colonisation by the British, the Kulin nation numbered more than 20,000 inhabitants.
There are several places around the world also known as Melbourne, in Antarctica, Canada, the UK, the US and, of course, Australia.
However, the location most commonly referred to when not referring to Melbourne, Australia is Melbourne, Florida, a small town near Orlando, Florida in the United States of America. It has a population of about 80,000. Originally called Crane Creek, the name was changed to Melbourne in honour of Cornthwaite John Hector, a former resident of Melbourne, Australia, and the first postmaster of the city.
The original inhabitants of Melbourne, Florida were Seminoles, American Indians.
Given that Melbourne, Australia is the much more populous city, you might expect it to be the main "Melbourne" referred to. Alas, that's not so. Some web services default to the smaller, Melbourne, Florida. To overwrite this, just search for "Melbourne, AU".