Alternate spelling - "cachability" (seems perhaps less popular/proper)
In Computer Science, the word "cache" is used in a specific sense to mean a place (usually in a specific memory location) where looked up values are stored temporarily so that they can be retrieved more quickly on the next request for them.
In web development, we cache pages or pieces of code, images, etc. in order to be able to serve more requests and take load off of application servers (ie, prevent the slashdot effect).
And so we talk about "caching" this page or this data, how to make data or pages "cacheable", and finally about the overall "cacheability" of certain pages or structures or apps.
"We need to evaluate the cacheability of our index page."
meaning something like
"We need to see how cacheable the index page is and to what degree."
The only problem is, the word cacheability isn't really a word... is it?
Is this a technical term that some computer folks are throwing around? Have they invented a new word? I'd be pedantic and say "it's not a word" and we're just using it wrong - go with cacheable and reform your sentences - but I know that not one of my coworkers would bat an eye if I were to use "cacheability" in a sentence, so it seems that it's meaning is clear in certain contexts and can express an idea that "cacheable" doesn't necessarily do as succinctly.