What is a digipack?

For part of my coursework I have to create a digipack, I am not yet quite clear on exactly what a digipack is. So, I am going to research digipacks and what they are.

Research from: http://musicians.about.com/od/ah/g/digipacksleeve.htm

"Digipacks are a type of CD packaging made out of card stock or other heavy paper/cardboard material. Digipacks can flip open like a book, or it can have three parts, so that one portion of the packaging opens to the right and one to the left, with the CD in the center portion. Usually, the portion of the digipack that hold the CD is made of plastic like a traditional jewel case CD - the plastic part is simply attached to the paper background."