I'd love to expand the term actually, because it's been misused to come to mean that something is community oriented, collaborative, even benevolent. Not even open source, but just the word "open". OpenAI for one. It's been abused for public image.
You're example of Linux is a bad one. Its contributions are corporate, but they are collaborative. With Android, Google dictates and others follow. Linux is not this way.
Samsung tears most of the UI layer off Android and installs their own look and feel. Google does the same with Pixel, Huawei does with their phones, and so on. You have to follow some of Google's rules to get Play Services, but Android varies immensely depending on vendor. Ditto for things like background tasks and battery life management.
The same applies to Linux. The kernel changes significantly on vendor as well, with changes making it upstream only if the famously tribal Linux maintainers find it interesting. I am sure that the same applies for code from Samsung or Qualcomm to the Android codebase.
You're example of Linux is a bad one. Its contributions are corporate, but they are collaborative. With Android, Google dictates and others follow. Linux is not this way.