Wiktionary
snap ring
n. A circular spring, having a small break in its circumference, used as a fastener; a circlip
WordNet
Usage examples of "snap ring".
My left wrist was pulled further then to the left, as she adjusted the chain on the left manacle, fixing the length of its play by a snap ring thrust through a link and about the couch ring.
Tupita, with the snap ring on the leash, fastened the leash on my right cuff, and Sita fastened the other leash on my left cuff.
Sam drove a piton into the wall, off to one side, clipped a snap ring to it, and snapped on the line.