Answer Description

Chrome OS is a proprietary operating system made by Google. It is mostly used on laptops known as Chromebooks. Android is not proprietary, the OS and it's source code can be found online for free. Many Android editions exist, some made by Google some made by others like Samsung or online communities.

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.