+/- ve notation for roots, positive/negative, etc.

So, help me out here: what does the notation -ve and +ve mean? I've seen it used with respect to Descartes's Rule of Signs, I think. It's usually used on polynomials, and I think it has something to do with whether a polynomial is positive or negative in a certain region. Or it might have something to do with the location of roots.

Is it an abbreviation? If so, for what?

Google and AcronymFinder didn't help at all on this one, because it's so short, and I'm wondering if it really is an acronym.

Thanks!