Comfort back

Comfort back: A rubber or plastic pad that goes over the clip end of a clip-on earring to cushion the earlobe.
Comfort Fit: A ring that adds to the comfort of the wearer by being curved on the inside of the shank.

Clip-back Earring: A hinged ring with a pad, called a "comfort back", at one end to secure the earring to the earlobe without requiring that the ear be pierced.
Cluster: Several stones grouped together in a jewelry setting.

See also: Channel, Earring, Oval, Faceted, Clip