Quadralink: A four link suspension system developed by Ford.

Quadrant: A mechanical lever shaped as a quadrant usually with three or more points for transmitting movement.

Quadrant and Pinion: Mechanism to raise and lower window. Similar to rack and pinion but with the rack on the circumference of the quadrant.

Quartz: A type of glass that will withstand very high temperatures.

Quartz Halogen Lamp: High intensity light bulb with a quartz glass bulb and filled with a halogen gas.

Quenching: A process of rapid cooling.