An unusually short, small person is sometimes called a dwarf. There are many different genetic medical conditions that can cause a person to be classified as a little person or a dwarf.
Some people are offended by dwarf, preferring to be called "little people," "LP," or "people of short stature." The general condition that leads to delayed growth is called "dwarfism." The noun dwarf is also used for an unusually small animal or plant, or as a verb meaning "make something seem very small," as when a new apartment building dwarfs the surrounding houses. The Old English root dweorg referred to a tiny creature from German mythology.