> By "variable" I mean a name with a value attached.

I'd just use "symbol" then. Symbols don't have much utility without a referent.

> Forth doesn't let you define these within procedures.

"within" vs "not within" seems like a distraction. Forth certainly allows defining your own symbols.

> Values are communicated implicitly on the stack in Forth, where other languages give them names and then use the names to say where the value goes.

Forth uses names, too. Other languages have unnamed expressions too. I just don't see the distinction you're drawing as meaningful.