Geography - abrasion and corrasion?

Corrasion is the wearing away of rock on the riverbed by abrasion (sandpaper-like action). I tended to only use abrasion in my answers though.

Oh wow, this brings me back...

And yeah, they're essentially the same thing. If you want to be nitpicky, Corrasion is the erosive action of particles carried by rivers(or wind/ice/etc.), while abrasion is the process by which they're broken down through friction.

I know this is an old thread, but I'm having the same problem. The CIE A level syllabus lists abrasion and corrasion as separate things, but what you describe as abrasion is what I was taught as attrition at IGCSE and attrition is not listed on the A level syllabus.