The problem is vocabulary. There's no mistake that there's a lineage from, say, C to JavaScript. Nor the lineage along the line of S-expression languages. But

The problem is vocabulary. There's no mistake that there's a lineage from, say, C to JavaScript. Nor the lineage along the line of S-expression languages. But when folks speak of JavaScript, or Java, they never refer to them as "C" or "a C". But when something is written in a S-expression language, suddenly it's all Lisp. "3D graphics is Lisp!" is the headline, then you learn it's some S-expr language that is not Common Lisp. Common Lisp is a Thing, much like C is a Thing. There are several implementations that call consider themselves compatible with Common Lisp. It has the closest ties and heritage to Lisp 1.5 ("the" Lisp). Scheme is a thing. When it comes to the "family of languages" idea, Scheme is most certainly practiced that way. There are a LOT of Schemes out there, all with various levels of compatibility and conformance to the assorted Revised Standard documents, but at the same time they all solve different problems. At a time there were several Lisps, but they were all essentially merged into Common Lisp. Now, we have "one" Lisp, and Scheme. Scheme forked off down its own branch, making conscious decisions to differ from the Lisps of the day. It's fair to point out that two Lisps survived that time, the other being Emacs Lisp. Then there's things like Clojure, AutoLisp, or even this PicoLisp which are S-expr based languages, but that's about where the similarity ends. They're as much the same as Java and C, and probably not even that close to be honest. I ported some simple C to Java. It was a fairly trivial mechanical conversion, but 80% of the code just drag and dropped across. But I would never call Java a C or vice a versa. Pascal is not an Algol, despite the heritage. "Structured programming language" is the vernacular. All of them are that: Algol, Pascal, C, Common Lisp, Schema, Java. But, of course, we don't disuss the s-expr languages in those terms, even though they are, indeed, supportive of "structured programming". When I see "Lisp" I think Common Lisp. Lisp == Common Lisp, Scheme == (one of the) Scheme, Emacs == Emacs Lisp (we almost never hear of someone doing XXX in "Emacs Lisp", it's almost always just "Emacs"). That's how I divide up the world. PicoLisp is as much a Lisp as Java is a C.