It refers to a section of the broad ligament situated between the mesosalpinx and the mesometrium in the female body. In the male body, it is known by the name mesorchium.
It keeps the ovary in position and acts as a protective covering for it. It joins the ovary with the broad ligament.
Get an idea about the physical appearance of this structure with the aid of these images.
Picture 1 – Mesovarium
Picture 2 – Mesovarium Image