"Midget" is a term used to describe a person of extreme short stature. It generally refers to a person with the medical condition of dwarfism. The terms "midget" and "dwarf" are often used synonymously, as both terms mean someone who has been short in stature since birth, but those terms were not originally synonyms.
Midget is a term that was originally coined in 1865, referring to an extremely short person with limbs similarly proportioned to his body as an average-size person's. P. T. Barnum indirectly helped popularize "midget" when he began featuring General Tom Thumb in his circus. Dwarf was originally used to denote those with short limbs as compared to those who had proportioned limbs. Like many other older terms, "midget" has become part of popular language, although it was often used in a pejorative sense. When applied to a person who is very short, midget is an example of the euphemism treadmill. Actor Hervé Villechaize insisted on being called a "midget" as opposed to a "little person", which irritated dwarf activists of the time.
Webster's New Collegiate Dictionary (Merriam-Webster, 1961) defines "midget" in the noun form as "a very diminutive person", and in the adjective form as "like a midget in size; very diminutive", hence its usage as a synonym for "miniature", as with cars.
According to the Online Etymology Dictionary, the term "midget" comes from "midge", meaning a sand fly, and the suffix "-et", meaning little or small. The fear of midgets is called Achondroplasiaphobia.