The majority of Forth systems are Forth interpreters, referring to the interactive nature of the language. A Forth interpreter can parse input, and execute it on the fly (using its OuterInterpreter). Alternatively, execution is delayed by compiling references to the parsed words into a list, which can be executed by the InnerInterpreter. Confusing, isn't it?
In fact, the OuterInterpreter is used for both interpreting source as well as compiling source to object. Often the very same piece of code is used for both tasks.
