Definitions
1.NounA surgical operation involving cutting into a lobe of a body organ, specifically , a procedure, now largely disused, involving severing connections between the prefrontal cortex and the thalamic region of the frontal lobe of the brain to treat certain mental illnesses.
2.NounAn operation involving the severing of the sympathetic nerve trunk.
3.NounAn act of removing or separating, and often disregarding or forgetting, something.