Answer Description
Google's Chrome OS is unique from other operating systems in that it primarily uses the web browser as it's user interface (Google Chrome). On some devices users can also install Android apps from the Google Play Store. It is not possible to run applications available for other operating systems like Windows and Mac on Chrome OS (unless they have a web version).
Wikipedia
Chrome OS is a Linux kernel-based operating system designed by Google It is derived from the free software Chromium OS and uses the Google Chrome web browser and Aura Shell (which runs from the browser process) as its principal user interface Google announced the project in July 2009, conceiving it as an operating system in which both applications and user data reside in the cloud: hence Chrome OS primarily runs web applications Source code and a public demo came that November The first Chrome OS laptop, known as a Chromebook, arrived in May 2011 Initial Chromebook shipments from Samsung and Acer occurred in July 2011
Chrome_OS - Wikipedia, the free encyclopedia