Pallidum: Part of what are called the basal ganglia of the brain which consist of the globus pallidus and the ventral pallidum. The globus pallidus itself is a pale-appearing spherical area in the brain. (Globus is a Latin word meaning a globe or sphere. Pallidus refers to its pallor relative to the surrounding brain substance.) The globus pallidus is specifically part of what is called the lentiform nucleus which, in turn, is part of the striate body, a component of the basal ganglia, large masses of gray matter at the base of the cerebral hemispheres of the brain.