accelerator

noun

• One who, or that which, accelerates.
• A device for causing acceleration.
• A substance which speeds up chemical reactions.
• A pedal causing the vehicle to accelerate when it is pressed.
• A chemical that reduces development time.
• A device that accelerates charged subatomic particles.
• A muscle or nerve that speed the performance of an action.
• An accelerator key.
• A light van to take mails between a post office and a railway station.