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 (sometimes styled as ChromeOS) is a Linux-based operating system designed by Google. It is derived from the open-source Chromium OS and uses the Google Chrome web browser as its principal user interface. Google announced the project in July 2009, initially describing it as an operating system where applications and user data would reside in the cloud. Chrome OS was used primarily to run web applications.All Chromium OS and Chrome OS versions support progressive web applications (such as Google Docs or Microsoft Office 365), as well as web browser extensions (which can resemble native applications). Chrome OS (but not Chromium OS) from 2016 onwards can also run Android applications from the Play Store. Since 2018, Chromium OS/Chrome OS version 69 onwards also support Linux applications, which are executed in a lightweight virtual machine with a Debian Linux environment.The operating system is now rarely evaluated apart from the hardware that runs it.