BMW produces a range of sport-utility vehicles called the X1, the X3, the X4, the X5 and the X6. Citroen makes the Xsara, the Xantia and the XM, while Nissan produces the X Trail and X Terra.
The flagship range from Jaguar since 1968 has been their XJ range. The "X" designation for Jaguar cars derives from experimental and as such the numbering system of their models has not always seemed logical. This is due to some projects not making through to final production.
Many car manufacturers are designing models for sale throughout the world and due to the differences in the pronunciation of "X" in some regions it is more common now for an "X" to be used as a prefix rather than as part of a name.