The most central part of the mind, which mediates with one's surroundings.
The self, especially with a sense of self-importance.
Any of certain masses of gray matter in the central nervous system, as the basal ganglia.
An encapsulated collection of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fiber.
A centre of intellectual or industrial force, activity, etc.
A benign cystic tumour on a tendon sheath or joint capsule.