How unique is ManagedThreadID?

Question

MSDN says: Gets a unique identifier for the current managed thread.

In what context does "unique" apply?

Is this unique per process?
per AppDomain?
per Machine?
per .NET runtime? (if I have both MS.NET and Mono running )

Answer 1

Thread ID is unique per process during thread's lifecycle, after thread terminated it's number can be reused.

Answer 2

Since threads from the ThreadPool also have to honour this property, and there is one ThreadPool per process (as stated in this MSDN article), I would think that the ManagedThreadId is most likely unique per process.