A continuously variable transmission (CVT) is a type of automatic transmission that can change seamlessly through a range of gear ratios. Unlike traditional transmissions with fixed gears, a CVT uses a system of pulleys and a belt to provide an infinite number of gear ratios, allowing for smoother acceleration and improved fuel efficiency. CVTs are commonly found in many modern vehicles, including those from manufacturers like Honda and Toyota. They help optimize engine performance by keeping the engine at its most efficient RPM, which can lead to better gas mileage and a more responsive driving experience.