How short is someone supposed to be to be considered a midget?
They must be at the most 4' 10". Though other factors must be present to be considered a midget.
4 feet 10 inches, and " little people" is the terminology used.
I'm a giant midget myself.
There is no actual height that's legally a dwarf. It's not just based on height, either. Traits of dwarfism are often stubbier arms and legs and larger heads and hands.
The modern term is "little person". And there are many conditions that make people smaller, so it's not a matter of height alone. The Wikipedia entry on "dwarfism" covers a lot of this very nicely. http://en.wikipedia.org/wiki/Dwarfism
About 4 feet
It's not the size, it's a defect that changes the whole body. They're short but a gene in the DNA has mutated to cause that, it's not about size, but conditions and gene mutation