These two words are practically interchangeable, but (in my mind at least) there’s a small difference that warrants them two different definitions.
If something is fluted, it means that the edges have been shaped to form a series of “waves.” If something is crimped, it has the same characteristics, but has a tighter “wave” along the edge.
It’s strange to put the definition into words in order to explain it. And, as always, it’s easier to see these things than to just read about them.
Here are a few examples of pieces with fluted edges:
Here’s an example of a piece with crimped edges:
And, just to confuse you some more, here is a “scalloped” bowl. The difference between “scalloped” and “fluted” is pretty simple – fluted items have that wave characteristic, an up-and-down motion to the form. If something is scalloped, it just means that the edges are not perfectly round, but come in and out (not up and down, too). Think of flower petals or even the way in which you would draw a fluffy cloud.