This is a basic question and some may laugh...but what is the difference between aftershave, EDT and cologne? I would think the magnitude and longevity of the scent but what else is different and what is the intended use of each type?
Scent, if any, is a secondary consideration.
Chris:Aftershave - any product you use after a shave (duh! ) intended to help heal, repair, protect skin. Scent, if any, is a secondary consideration.
Cologne/Edt - basically, perfume for men. There's a traditional gradation of scents from least to most concentrated (eau de cologne -> eau de toilette -> eau de parfum -> perfume), but there's no real hard and fast rule what's what anymore. EdT is more concentrated that EdC, but marketing / branding plays as much into it as anything.
To confuse things even more, there are hybrid products that have the benefits of both, and some products are just plain mis-named. Most "famous person" named aftershaves are really just scent and alcohol, there's no real skin-healthy ingredients in there.