[elteto]

I would define a concurrent program as one with multiple independent flows of execution. Whether they are scheduled on multiple CPUs at the same time or just one is what makes them parallel or not.

If you look at a what happens inside a CPU then you probably could say a uniprocessor has some degree of parallelism, but this is not a common point of view AFAIK, it is too low level. Also, the execution contexts inside a pipelined CPU are not entirely independent, you can have pipeline stalls due to dependencies. This is not the case with, say, two application threads running independent tasks.