Definition of solar plexus
1
: a nerve plexus in the abdomen that is situated behind the stomach and in front of the aorta and the crura of the diaphragm and contains several ganglia distributing nerve fibers to the viscera
2
: the pit of the stomach;
specifically
: the part of the abdomen including the stomach that is particularly vulnerable to the effects of a blow to the body wall in front of it
