I was hoping the question was philosophical, as in "what's the slip coverness of slip covers," because as is I couldn't help but chuckle.

And for the record, the round, plastic thing inside the case with the shiny, reflective side and a picture side is a dvd disc.

Well, technically, I call that a slipcase.

Actually, I had no idea what they were talking about until the picture was posted. 99.9% of the DVDs I buy don't come in such a case.

The piece of paper that goes inside the DVD case is called a slipsheet.

I always thought the piece of paper inside the case itself was an insert? Never heard slipsheet before...

And the VD itself is a freudian slip.

A Slipcover, also known as a slipcase or sleeve, is the open-ended, decorated cardboard box that covers the plastic case that holds a set of DVDs purchased, for example, at a retail store. The slipcover is not the plastic case that holds the DVDs, it just slides over and protects that case and typically provides information describing the contents of the retained DVDs. As a point of interest, before DVDs were even invented, the term slipcover was used to describe a fabric covering that slipped over, dressed up and protected the body of a chair, sofa or other furniture. So, in this modern era, the DVD slipcover provides essentially the same function for a DVD case as the old fabric slipcover did for furniture.

Now, the DVD case also contains a colorful paper display that is encased in a plastic window adhered to the body of the DVD case. This paper display is known in the DVD industry as a "slick." The slick is not a slipcover even though it can be slid in or out of its transparent envelope on the DVD case.

Attached are a couple pictures to illustrate a DVD slipcover, a DVD slick and an associated plastic case. I was going to include a picture of a furniture slipcover, but decided that is overkill.

Don't quote me verbatim but having dealt with the Technicolor plant (formerly Cinram) in the past they refer to it as a "trap sheet cover" being either "4/4" (full colour/double-sided print) or "4/0" (full colour/single-sided print)

The page or booklet inside is the "insert" or "insert booklet" if it is more than a single page, non-folded.

The slipcover can be called a "slipcase" which is a single-walled cardboard case printed 4/0 with two open ends. "Half-double wall" slipcases are usually printed 4/0 with a flap and one open end on the side - think TV series that contain slimline cases.

Disney has their own term for a slipcover - O-ring.

Welcome to the forum, EXPLAINER! Hope you'll stick around and solve many other mysteries from years past.