The term Forth compiler is ambiguous, or at least easily misunderstood. Even a ForthInterpreter uses some compiling mode for words added.
What is - in the Forth world - commonly referred to as compiler, is the part of the ForthInterpreter which compiles Forth source to ThreadedCode. From this point of view, Forth interpreter and Forth compiler are two (very similar) aspects of the same Forth system, and used almost as equivalents of each other.
Less commonly does Forth compiler describe a program which generates a stand-alone executable target program, though there do exist Forth compilers which do exactly that. Those are often referred to as target compilers or native code code compilers. Sometimes these compilers are not interactive Forth systems, and lack some characteristics required by misc ForthStandards, therefore some of them could, strictly speaking, not even be called ForthSystems.
