Well, really, we were not trying to be word police here; I don’t see any reason why you couldn’t just use the word “simplify” on occasion. But when there is a more precise term available, use it. For example, when you multiply two polynomials you might expand the product, or you might leave it in factored form. When you substitute numbers into the quadratic formula, then I think it is appropriate to talk about simplifying the resulting numerical expression.