Correct.

In this light I'd suspect that the message "your device is loading a different operating system. " that is shown at boot-up is coming from the ROM. The Graphene OS logo shortly after is likely coming from the OS.

I would regard GrapheneOS in the same way an Linux operating system is refered as a distribution "distro".

You got AOSP and then you got a lot of different distributions of it such as Android, GrapheneOS, CalyxOS, LineageOS and the OEM variations of Android.

The same way the operating system that is free of distributions FreeBSD has several distributions, GhostBSD, NomadBSD.

I think the term distro is very much applicable in this case.

    VEECCdYKYi

    Exactly this. Android "ROM" is just a scene term similar to a GNU/Linux "distribution". An Android "ROM" is basically an "AOSP distribution". Some are just LineageOS with some tweaks, some have a large changeset from AOSP such as GrapheneOS. Commercial non-free ones like Samsung's OneUI could also be called an Android distribution/ROM with the same logic.

    Meanwhile there is only one iOS, for contrast.

      raccoondad thanks for the explanation.. I tried to explain it here too in the past multiple times but the ROM thing comes back again and again :-)
      It's so silly. If it would be really a ROM, no flash possibility, then putting graphene os into the cellphone would most probably mean some soldering, good luck with that... Software update? get your tools and skills ready.. :-)))

          VEECCdYKYi different distributions of it such as Android, GrapheneOS, CalyxOS, LineageOS and the OEM variations of Android.

          Android isn't a distribution of Android (aka "AOSP") -- that's like saying Linux is a distribution of Linux. What I think you mean is Google Pixel (factory OS) as a distribution of Android.

              andrej567 "Software update? get your tools and skills ready"

              They could make software updates little cartridges like an NES XD

                  secrec
                  I might be wrong but. Well Android and AOSP aren't the same. Android is AOSP with Google's proprietary components built in. Android is trademarked and for a phone to sell it as Android phone they must add Google spyware to it. Amazon's FireOS for example aren't based on Android but on AOSP, same Huawei's HarmonyOS.
                  Android is ASOP with Google bloat.

                      VEECCdYKYi "Android" is the blanket term that covers everything, including GrapheneOS.