Ultrabook vs. Chromebook — What's the Difference?

Ultrabook is a marketing term, originated and trademarked by Intel, for a category of high-end laptop computers. They were originally marketed as featuring ultra thin form factor and light weight design without compromising battery life or performance, and when the term was originated they generally were enough smaller than average laptop models to qualify as subnotebooks.

A Chromebook (sometimes stylized in lowercase as chromebook) is a laptop or tablet running the Linux-based Chrome OS as its operating system. Chromebooks are primarily used to perform a variety of tasks using the Google Chrome browser, with most applications and data residing in the cloud rather than on the machine itself.

(computing) A very lightweight and thin portable computer the areal size of a notebook computer or subnotebook.