Middle-earth is the setting of much of J. R. R. Tolkien's legendarium. The term is equivalent to the term Midgard of Norse mythology, describing the human-inhabited world, i.e. the central continent of world of Tolkien's imagined mythological past. Tolkien's most widely read works, The Hobbit and The Lord of the Rings take place entirely in Middle-earth, and Middle-earth has also become a short-hand to refer to the legendarium or its "fictional-universe".
Within his stories, Tolkien translated the name "Middle-earth" as Endor (or sometimes Endórë) and Ennor in the Elvish languages Quenya and Sindarin respectively, sometimes referring only to the continent that the stories take place on, with another southern continent called the Dark Land.
Middle-earth is the central continent of Earth (Arda) in an imaginary period of the Earth's past (Tolkien placed the end of the Third Age at about 6,000 years before his own time), in the sense of a "secondary or sub-creational reality". Its general position is reminiscent of Europe, with the environs of the Shire intended to be reminiscent of England (more specifically, the West Midlands, with Hobbiton set at the same latitude as Oxford).
* You ain't nothin' but a hound dog
Just cryin' all the time
You ain't nothin' but a hound dog
Cryin' all the time
Well, you ain't never caught a rabbit and you ain't no friend of mine
[* Repeat]
[** Repeat]
Well they said you was high classed
Well, that was just a lie
Yeah! they said you was high classed
Well, that was just a lie
Girl you ain't never caught a rabbit and you ain't no friend of mine
[* Repeat]
Well, you ain't never caught a rabbit and you ain't no friend of mine