An accelerator is something that makes things speed up or happen faster.

In a car, the accelerator is the pedal you press to make the engine work harder and the car go faster. The harder you press it, the more the car accelerates. Some people call it the gas pedal because pressing it sends more fuel to the engine.

In science, a particle accelerator is a machine that speeds up tiny particles to enormous speeds, sometimes close to the speed of light. Scientists use these giant machines to smash particles together and study what happens, helping them understand how the universe works. The Large Hadron Collider in Switzerland is the world's most powerful particle accelerator.

The word also describes programs that help new businesses grow faster. A startup accelerator gives young companies money, advice, and connections to help them succeed more quickly than they could on their own. These programs accelerate the normal process of building a business.

You might hear someone say that a discovery acted as an accelerator for progress in medicine, meaning it sped up how quickly doctors could help patients. Anything that makes a process move faster can be called an accelerator.