The term 'THE 'D' IN CD' is an acronym for the phrase 'DISC'. A DISC is a type of storage medium used to store digital information, such as music, movies, and computer programs. It is typically made of plastic and has a data layer that can be read by a laser. CDs, or Compact Discs, are one of the most popular types of discs, and they are used to store audio recordings. The 'D' in CD stands for DISC, which is the physical medium used to store the audio recordings.