The term accelerator is often used in the same sentence as the terms launchpad and incubator, but the three have their own subtle differences. Many accelerators also operate a launchpad and/or incubator to help them progress the projects they are accelerating.
An accelerator is a business or organization that supports existing early-stage businesses (often business that are yet to earn any revenue) by accelerating the growth of their product. Accelerators often focus on a certain niche or sector, e.g. finance, and also mentor the businesses that they take on. Accelerator can sometimes offer finical assistance to the juvenile businesses that they take on. These businesses must apply to be a part of the accelerator and the accelerator then accepts or rejects their applications.