What is an ISRC?

Once you have been in the recording industry for a while, you start to pick up on the language or shorthand of the industry.  I remember the first time I heard someone ask me about ISRC codes.  I had no idea what they were talking about.  Working on the legal end of the industry, there really was no reason for me to know.  However, I have many producers and independent recording studios as clients.  When I learned that they did not know what an ISRC code was, I figured I would do some investigation on our behalf.