Hard disk drive platter

Circular disk on which magnetic data is stored in a hard disk drive

A hard disk drive platter or hard disk is the circular magnetic disk on which digital data is stored in a hard disk drive. The rigid nature of the platters is what gives them their name. Hard drives typically have several platters which are mounted on the same spindle. A platter can store information on both sides, typically requiring two recording heads per platter, one per surface.

This keyword could refer to multiple things. Here are some suggestions: