A superhuman is an entity with intelligence or abilities exceeding normal human standards.
Superhuman can mean an improved human, for example, by genetic modification, cybernetic implants, or as what humans might evolve into, in the distant future. Occasionally, it could mean an otherwise "normal" human with unusual abilities, such as psychic abilities or exceptional proficiency at something, far beyond the norm.
Superhuman can also mean something that isn't human, but considered to be "superior" to humans in some ways. A robot that easily passed the Turing test, and could do some things humans can't, could be considered superhuman. A very intelligent or strong alien could be considered superhuman.
The concept of the superhuman is quite popular in science fiction, where superhumans are often cyborgs, mutants or genetically engineered. The greatest publicity of the concept is, of course, comic book superheroes, such as Superman. The term is often used in discussions of comic book characters because the terms Superman and super hero are registered as trademarks. Superhuman characters in various comics, role-playing games and other entertainment media have also been referred to as metahuman or posthuman.
One type of superhuman described in science fiction stories, particularly during the Atomic Age, derives from the concept of mutation. In such tales, a human being would mutate into or give birth to a being that either has powers not yet exhibited by humans, or else motivations entirely different from those human beings, or both. In some stories, these beings are either unable to get along with "normal" humanity, or replace them entirely, causing the extinction of present-day humanity.
Such superhumans are sometimes referred to as a "new species" (or "successor species") of humanity; in a number of fictional franchises, such as those of the Tomorrow People or the X-Men, these groups are even given the binomial nomenclature Homo superior, to distinguish them from Homo sapiens. The main problem with this concept is that it is dominated by a misunderstanding of the theory of evolution. Mutation takes place, but it is only a summation of the interactions of genes with the environment for many generations which eventually leads to the development of a new species, and then further time has to occur before one species becomes extinct while another, not necessarily the mutated species, survives. It is also possible (indeed, common) for two species from the same ancestry to survive at the same time, under separate environmental conditions, or occupying different niches. And it is only a value-judgement by humans which declares that the different characteristic of new species is "superior". But the notion of progress is inherently built into this genre of stories.
However, other stories turn this notion on its head, showing the disadvantages of a supposedly superior ability or quality; for example, in Briar Patch by Dean Ing, a group of ancient hominids were portrayed as a largely pacifistic, telepathic and highly empathic species who could not stand to inflict pain, even while hunting; they were eventually overwhelmed and exterminated by the less sensitive but more ruthless Homo sapiens.
Many other types of superhumans are also portrayed in science fiction. For example, the Dune series contains several varieties of superhumans, ranging from those produced by selective breeding to chemical enhancement or lifelong training in as yet uninvented mental and physical disciplines, and artificial lifeforms such as the Face Dancers. The Dune prequels also describe nearly-immortal brain-in-a-jar cyborgs called Cymeks and advanced artificial intelligence. The CoDominium universe has superhumans produced by artificial and natural selection and by genetic engineering; for example, the alien Moties have been bred for thousands of generations to be far better than humans at their caste's specific job, such as Engineer or Mediator. Many other fictional aliens, such as Vulcans, Kzinti and Mork from Ork have greater than human abilities or powers, sometimes simply for the purpose of making them seem more advanced or more "alien", other times simply for dramatic reasons (particularly if they are the antagonists of the story).
In Marvel Comics the term superhuman is part of a "power classification system" and applies to aptitude (usually physical) far beyond the range attainable by normal human beings. An athlete is a normal human in extraordinary physical condition, such as a weight lifter or boxer. Peak human is applied to physical abilities that are nearly, but not quite, beyond the limits of the best of humans. Enhanced human refers to superhuman abilities some distance beyond the limits of humans, such as being able to lift a small car but not a tank, and is a term for "light" superhuman abilities. Then comes the level of the "superhuman." Characters with a superhuman attribute are far beyond normal human abilities.
These categories are very rarely referenced in the actual stories themselves. Instead, they are usually reserved for descriptive articles such as the The Official Handbook of the Marvel Universe.