disc

1a :  the seemingly flat figure of a celestial body the solar diskb archaic :  discus

2 :  any of various rounded and flattened animal anatomical structures; especially :  intervertebral disk — compare slipped disk

3 :  the central part of the flower head of a typical composite made up of closely packed tubular flowers

4 :  a thin circular object: such asa usually disc :  a phonograph recordb :  a round flat plate coated with a magnetic substance on which data for a computer is storedc usually disc :  optical disk: such as (1) :  videodisc (2) :  cd

5 usually disc :  one of the concave circular steel tools with sharpened edge making up the working part of a disc harrow or plow; also :  an implement employing such tools