What is a 4 x 4 vehicle?

A vehicle where all four wheels are driven. Most cars only have two wheels that rotate via the engine and propel it along, the other two just hold up the corners.

Having all four wheels driven, gives greater grip and more traction in slippery conditions in commercial vehicles, or better stabilty round corners in sports cars.

It's pronounced 'Four by Four' and like the animals that went in 'two by two' into the Arc, all four wheels drive 'four by four'.