There is no standard definition of what a Turkey Crown actually is, though. Most often, and strictly speaking, it is and should be the top part of a turkey, with the legs, wings and undercarriage cut away. The bones are left in the top part in order to retain the natural look of a roasted turkey when it is cooked. Some come stuffed. That being said, some butchers define a Turkey Crown as a turkey with just the legs and wings removed. And a few butchers will sell a Saddle of Turkey (which is boneless breasts still joined at the top) as being a "Turkey Crown."
http://www.cooksinfo.com/turkey-crown