A Chromebook is a laptop running the Linux-based Chrome OS as its operating system. The devices were originally designed to be used primarily while connected to the Internet, with most applications and data residing in the cloud. The original Chromebook was an example of a thin client.
A rack and pinion is a type of steering gear in which a pinion on the end of the steering column engages with a horizontal rack (= flat-toothed bar.) COLLOCATIONS: ~ steering. The speed-sensitive rack and pinion steering set-up was light and precise.
A good example of a rack and pinion gear system can be seen on trains that are designed to travel up steep inclines. The wheels on a train are steel and they have no way of griping the steel track. Usually the weight of the train is enough to allow the train to travel safely and at speed along the track.