My definition is not Websters, but it's the rule I've found to be most helpful to me. And it's something I try to live by.
Morals are a set of standards that one (or a group) will judge others on.
Ethics are a set of standards that one (or a group) will judge their own self on.
Now the Ethical "set of standards" should be exactly the same as the Moral "set of standards". Also, one should run through their own ethics, e.g. "what would I do in that situation", and what would allow oneself to break one's own ethical standards before even starting judgment on someone else's morals.
I tend to find when I do that, my ethic standards go up and my moral standards go down.
That's why I tell people "I try to have high ethics, and very little morals".
...hope that made sense......