Almost right. The commonly accepted definition of "multitasking" is a systems that "appears to be" running more than one program (or app) at the same time. They don't need to both be multi-threaded and you don't need to have many of them. Two single-threaded apps running at the same time is multitasking.
I say "appears to be" because under this definition, even a single-core system can be "multitasking" simply by switching which app is running often enough that no human can tell that only one of them is running at any moment.
I'm a lead software engineer who's been writing software for over 35 years. I've written everything from tiny embedded systems to massively multi-threaded multi-tasking multi-user networked systems. To be blunt, if I don't know what multitasking is, then nobody knows...
Android, by virtue of being built on Linux (which is already multitasking) is multitasking. Debating this is pointless. If you don't think it is multitasking, I think you need to define your terms more carefully.
I suspect that you're using the literal multi-cores-multi-processes definition rather than the more commonly used anything-that-looks-the-same-to-a-human definition. If this is the case, I'm sorry to break this to you, but you're fighting a loosing battle. Nobody cares that there is a low-level technical difference because it doesn't matter. They both look the same to the user...
If you're using some other definition, then please spell it out and explain the differences rather than being pointlessly condescending.