Thomas Munro <thomas.munro@gmail.com> writes:
> I think the incorrect spelling fits the usual pattern (movable,
> valuable, believable, ... with moveable accepted but dying), and it's
> definitely "caching" without the -e-, so it's probably a tempting
> mistake to make, but apparently we're making new words out of bits of
> French with the C preprocessor ## operator and ignoring all that. I
> bet it's "cachable" en français though. My Oxford Concise lists only
> the -e- form, so you have my vote. The online Merriam-Webster (I
> think that's the main reference for US spelling?) doesn't list either
> and suggests I might be looking for cashable.
I tend to look to OneLook Dictionary Search:
https://www.onelook.com
Their set of dictionaries has multiple entries for "cacheable"
and only one for "cachable". I don't agree that the latter is
wrong exactly, because some people evidently use it and English
has no Académie Française to legislate what is right; but it's
clearly the less common spelling.
regards, tom lane