Glossary “four wheel drive” Definition:
A vehicle having a driving axle in front and rear, so all four wheels are driven. Also referred to as 4WD.

Glossary “four wheel steering (4WS)” Definition:
System whereby all four wheels are used to steer a vehicle.

Glossary “four wheeling” Definition:
Off-road travel in a four-wheel vehicle.

Glossary “four speed transmission” Definition:
Transmission providing four forward-gear ratios, one reverse ratio, and neutral, permitting closer matching of engine speed to load requirements than a three-speed transmission.

Glossary “four stroke cycle” Definition:
1). A cycle of engine operation whereby the combustion occurs in every cylinder on every second revolution of the crankshaft. 2). A complete cycle includes intake or induction, compression, combustion or expansion, and exhaust. 3). Also known as four cycle.

Glossary “four stroke engine” Definition:
An engine in which a piston must complete four stroke to complete one cycle. The four strokes are; intake, compression, power, and exhaust. Also known as Otto-cycle engine.