Nissan’s brand name for its continuously variable transmission technology is Xtronic.
Xtronic is Nissan’s marketing name for CVT technology supplied primarily through Jatco, its major transmission partner. Unlike a conventional automatic with a fixed set of gears, a typical belt-and-pulley CVT varies the effective diameters of its pulleys continuously, allowing many ratios between its lowest and highest settings.
Nissan used an earlier toroidal CVT called Extroid in the Cedric Y34 in 1999. In 2003, the company shifted to pulley-based CVTs marketed as Xtronic. This history is why Extroid and Xtronic can both appear in discussions of Nissan CVTs, but they are not the same branding or design.
Drivers sometimes describe a CVT as having no gears. More precisely, it has no fixed stepped gear ratios in the conventional sense, although software can simulate steps to make acceleration feel familiar. Lineartronic is Subaru’s term, Multitronic was used by Audi and Volkswagen, and Steptronic is BMW’s name for a manual-mode automatic rather than a CVT brand.