Source: "The Invention of Forth", by Chuck Moore. https://colorforth.github.io/HOPL.html

Forth should be considered a family of languages; Anton Ertl took its picture some time ago [1].

Chuck Moore agrees I think with the idea [2]:

That raises the question of what is Forth? I have hoped for some time that someone would tell me what it was. I keep asking that question. What is Forth?

Forth is highly factored code. I don't know anything else to say except that Forth is definitions. If you have a lot of small definitions you are writing Forth. In order to write a lot of small definitions you have to have a stack. Stacks are not popular. Its strange to me that they are not. [...]

What is a definition? Well classically a definition was colon something, and words, and end of definition somewhere.

    : some ~~~ ;

I always tried to explain this in the sense of this is an abbreviation, whatever this string of words you have here that you use frequently you have here you give it a name and you can use it more conveniently. But its not exactly an abbreviation because it can have a parameter perhaps or two. And that is a problem with programmers, perhaps a problem with all programmers; too many input parameters to a routine. Look at some 'C' programs and it gets ludicrous. Everything in the program is passed through the calling sequence and that is dumb.

[1] https://www.complang.tuwien.ac.at/anton/euroforth/ef04/ertl0...

[2] https://www.ultratechnology.com/1xforth.htm