1. Referring to a fold or membrane which envelops and supports an internal organ; such as, the vertebrate mesentery (a membrane which holds the spinal column together).
2. Pertaining to the mesentery which is a membranous fold attaching various organs to the body wall; such as, a fatty membrane placed in the middle of the intestines, and to which they are attached.

This prevents them from becoming entangled with each other by convolutions (coiling or twisting or winding together).