The use of the metal disc was invented in 1978.

A round metal disc hung on a light chain around his neck.

The top metal disc reflects the radiant heat onto a small area.

Three keys attached to a metal disc had been found in the pocket of the woman's coat.

Think about it: Would you want to grab and hold on to a heavy metal disc that was spinning really fast?

But feeling around, she found no metal disc or any other escape mechanism.

The back of the device has small metal discs that work like electrodes.

Why replace metal discs, which have served well for many years and are easy to make?

The two metal discs are then pushed together to create a sound similar to that of a milk bottle being hit.

I saw that a tiny metal disc lay on the floor beneath it.