This week, with my GP, I played:

@Cadet Stimpy "centaur" has been re-analyzed into "cen" + "taur" (whatever these two words may mean) and "taur" has been re-used to be combined with other words "hentaur", "cheetaur", etc., as if it were a meaningful unit. But "taur" doesn't mean anything that warrants its use in "cheetaur", "hentaur", etc.

Same with "hamburger". It has been re-interpreted as "ham + burger" so you can switch "ham" with whatever you want, even though there has never been ham in a hamburger in the first place.

By contrast, "werewolf" has been productively reused in words such as "wererat" or "werebear", but here that makes sense because "werewolf" is literally "man + wolf", so you can have "man + rat", "man + bear", etc.

@Zerbique Thanks, Z, now I get it. Re-reading the first burger Comment, it makes sense now. I dunno why I didn't get it the first time. Guess I was a bit delirious. 😀 I wouldn't doubt if there's some bizarre word that actually defines when you combine words that don't really go together. It might be Morphology. But there is this!

@Cadet Stimpy It sure falls within the fall of morphology (the study of the formation of words, if I am not mistaken).

Actually, fun fact. In the "hamburger" article in Wikipedia, the emergence of "burger" is described as an instance of back-formation. But "burger" from "hamburger" is also quoted as a featured example in the rebracketing article. And it's also a key example of the folk etymology article.

"Folk etymology" is just a despising, classist word to say "people do weird things with language". Back-formation and rebracketing are examples of such "folk etymology".

Rebracketing occurs for hamburger (hamburg + er > ham + burger): how you split the word into parts has changed. Because of that "burger" got re-interpreted as a unit that can combine, leading to the back-formation of the other words of the family.

So, terminology is muddy, uninsighftul, and a bit haughty. But Wikipedia is nice and helpful as usual.