The terms are actually pretty confusing. Yes, 'macroevolution' was coined by creationists, as you might have guessed. Their argument is that small mutations happen over time, but that it only leads to variations among species and not new species altogether (at least this is how it was explained to me). I think this definition has changed since speciation has actually been observed in recent history (source: http://www.talkorigins.org/indexcc/CB/CB910.html), but again all the definitions I've heard on this are pretty fuzzy. It's amazing how people will cling so tenaciously to debunked ideas for the sake of preserving their beliefs.