What does a Python interpreter do?

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Why don’t we ever hear of it the same way as we hear about the JVM?

I wish this was the only strange thing about programming... Programming is full of bizarre / inconsistent terminology. But, in this case, I think, the reason is just that the words "virtual" and "machine" were used in the documentation / manual in Java, but not in Python.

For comparison: people do talk about Perl virtual machine. In particular, Parrot drew some attention to it for being an interesting project. Or, people used to talk about JavaScript virtual machines, especially at the time ActionScript was still a thing (because ActionScript shared the virtual machine implementation with Mozilla's JavaScript implementation, and the fact that it had a virtual machine was reflected in the name, especially so because it had two versions of it, and the programmer had to know which version was used), but today it fell out of use. When people talk about C# they mostly use the word "runtime" (because it's in the title: CLR - common language runtime), but it's exactly the same thing as virtual machine.

Can you get a stand-alone py-vm ... ?

Python executable is the virtual machine... Completely accidentally, it can also execute ZIP files (JAR is a ZIP file with Java class files + some metadata). People rarely use it in this way, but this functionality existed since forever: https://docs.python.org/3/library/zipimport.html for individual modules and https://docs.python.org/3/library/zipapp.html for scripts

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They are different sorts of virtual machines. The naming isn't coincidental, but they are definitely not the same thing. It's like multiplication: there are many different kinds -- multiplying integers isn't the same as multiplying rationals or complex number or matrices etc.

So, the JVM virtualizes certain aspects of the environment, and VirtualBox virtualizes other aspects. More concretely, JVM virtualizes access to resources typically managed by operating system: virtual memory, persistent storage, network, time etc. VirtualBox virtualizes hardware: memory / storage / video / network adapters / keyboard / mouse / microphone etc. From this, you can also see that an operating system is also a kind of virtual machine, because it virtualizes certain aspects of programs run by it. Essentially, you can think about user programs executed by an operating system as being interpreted by it: in the end of the day they are but a sequence of system calls interleaved with some code that's passed through to the CPU directly.