c.d.

cash discount.

* * *

cd.,

cord or cords.

c.d.,

cash discount.

Cd (no period),

cadmium (chemical element).

CD (no periods) or C.D.,

1. certificate of deposit.

2. civil defense.

3. compact disk: »

Because there is no groove in a CD, there are none of the mechanical problems involved in keeping a phonograph needle in a groove (Suburbia Today).