Word is an internal call, it's a function, but the key is that the parameters and local variables are on the data stack and are separate from the return stack.

Word is an internal call, it's a function, but the key is that the parameters and local variables are on the data stack and are separate from the return stack. I can call many levels without touching the data stack! Impossible in other languages. However, this does require practice and a change of mindset. At runtime, the dictionary doesn't exist, and under certain conditions and with the correct compiler, the stack doesn't either; it's converted into registers.