The obvious (just taking your lead of course....)
r's.....hmm, that doesn't work though, does it?
nd's....hmmm, that doesn't work either, does it?
Okay, Mr. BRDof3, I'm stumped and too tired to check the online dictionary so help me out here. Up to the challenge again?
(Everyone else: the word is edge and you can totally ignore Mr. BRDof3 and me.)