Named for the German aerodynamicist W. Kamm, who discovered that drag begins to increase after the rear of a car's cross-sectional area is reduced to 50 percent of the car's maximum cross section.

A small block usually fitted in a notch between a shaft and a hub to prevent slippage of the two parts.

A downshift in an automatic transmission caused by depressing the throttle.

A sensor mounted on the engine that is designed to detect the high-frequency vibrations caused by detonation. By employing a knock sensor, a computerized engine-control system allows an engine to operate very near its detonation limit: thereby improving power and efficiency.

A single wing nut for fastening a wheel to the hub. Easily removed and replaced, it is struck (knocked off) with a mallet on the wings.

When your engine knocks or pings, it is a sign that the engine is firing at the wrong time. This could be because of bad ignition timing, an incorrect grade of gas, or another ignition or fuel system fault.

International agreement among industrialized countries to reduce greenhouse gas emissions negotiated in Kyoto, Japan in December 1997. Canada committed to reduce its greenhouse gas emissions by 6 percent of 1990 levels between 2008 and 2012.