Michael Pollak wrote:
>
> > working on a list of toponyms which originate as proper place names but
> > then come to have a more generalized meaning...any other good ones?
>
> Marathon
> Utopia
> Doolally
>
"Utopia" was a coinage through a pun on greek prefixes, "eu" meaning good and "u" meaning no before a common noun for place. (I'm gambling on my memory and haven't checked, and my memory often not a good gamble.)
Carrol