The main point is that it doesn't really matter. Anyone can define a term in a slightly different way, and usually various authors adapt the meaning to the various contexts within which they use those terms.
You will not gain any enlightenment from trying to figure out which one is "right" and which one is "wrong". Quotes taken out of context are especially uninformative.
The important thing is to understand the underlying ideas without reference to the vocabulary items used to refer to them.