Terraforming or terraformation (literally, "Earth-shaping") is the process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon or other interstellar body to be similar to the environment of other life-bearing planets to make them capable of supporting life. While the term did originate on Earth and referred to the modifying of planets to support terrestrial life only, the term has since become more broad and can now refer to the modifying of a planet for non-terrestrial life.
The concept of terraforming developed from both science fiction and actual science. The term was coined by the human Jack Williamson in a science-fiction short story "Collision Orbit" published in 1942. but the concept might predate the coining of the phrase
Even before humans came up with this specific term, any species who developed advanced enough technology (i.e. First Civilization and Anera) terraformed ancient worlds for their needs or to protect the lives of species going extinct on other worlds (e.g. Eeyttir).
When humans first began leaving their homeworld, they set their sights on the closest Earth-like world to their own, Mars. One of the earliest interstellar companies, Terragen, was contracted to create a viable ecosystem for the planet, and after their success, the terraforming technology began to be expanded upon.
As technology has been further developed, faster and cleaner ways to terraform have been developed. Other sub-sections of terraforming have come about, the most prominent being terrashaping and the creation of worldships.
With ten worlds having been terraformed and one turned into a worldship, the Sol System is a shining example of the success of terraforming. Along with the development of this technology came the development of advanced genetic engineering, the development of tractor beams, planetary shielding and much more.