A ring is an area surrounded by two concentric circles, which can be considered as a hollow circle. A circular ring is characterized by having two radii, an inner diameter and an outer diameter, and the difference between the two is the width of the circular ring. Rings can be used to design jewelry, watches and other items, and can also be used to make industrial products such as tires and pipelines.

The disc is a complete circular plane with no hollow part. Disc is usually used to represent disc-shaped objects, such as CD, DVD, record, etc. Disc can also be used to make frisbee, turntable and other toys.

Generally speaking, a ring is hollow and surrounded by two concentric circles, while a disk is a complete circular plane.