[CSS Abstract] What kind of lenguage is CSS?

All CSS documents begin with the purpose of CSS:
"CSS is a language for..."
This declaration has been changing by time goes.

But I could not find a current definition of what kind of language is CSS.

Today (2015) and

based on all documents CSS (whatever their status)
and if (we can take as valid the definition of "programming language
<https://en.wikipedia.org/wiki/Programming_language>" from the wiki)


is Css a "programming lenguage"?
why yes?
why not?
If that definition is not valid, what else used to determine if "css is a
programming lenguage"?

Thanks in advance