It should also be mentioned that when people use Fortran, it is usually because they need the fastest numerical processing available. An interpreter would usual

It should also be mentioned that when people use Fortran, it is usually because they need the fastest numerical processing available. An interpreter would usually not meet that need. With JIT compilers embedded in interpreters, the difference is blurred, since the result is machine code, unlike traditional bytecode interpreters, that usually are an order of magnitude slower than compiled code. That said, I'm also not aware of any Fortran interpreters, and it would surprise me if there is one.