Disk and disc have very similar pronounciation, but they are very different: 2 alternative spelling for things that are generally thing and circular geometry. For the most part the words „disc” and „disk” can be used interchangeably to describe these flat, rounded objects. The terms and the objects appear in fields such as computers, media, science, anatomy and automotive mechanics. Some of these fields primarily use one spelling, others use both, depending on the specific object. In many fields the spellings can be used interchangeably, but generally in computer technology the word disk refers to the magnetic storage (hard disks, floppy disks or diskettes) while disc refers to optical storage (compact discs or CDs, digital versatile discs or DVDs).
In computers and media these 2 words refer to storage devices for data, music and videos. You can store all kind of files on them, but the difference in their structure give you different ways to write, organize and read the data from them.