/ˈgaNGglēən/
Noun, pl. ganglia
(Anatomy)
1. A biological tissue mass, most commonly a mass of nerve cell bodies. Cells found in a ganglion are called ganglion cells, though this term is also sometimes used to refer specifically to retinal ganglion cells. (wikipedia.org)
2. A mass of tissue. (wikipedia.org)
3. A benign cyst found on aponeurosis or tendon, usually at the wrist or dorsum of the foot. (biology-online.org)
4. A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fiber. (Google Dictionary)
5. An abnormal benign swelling on a tendon sheath. (Google Dictionary)
(Neuroanatomy)
1. A cluster of interconnecting nerve cells outside the brain. (wikipedia.org)
2. A network of cells forming a nerve center in the nervous system of an invertebrate. (Google Dictionary)
3. A well-defined mass of gray matter within the central nervous system. (Google Dictionary)
Word origin: From Greek ganglion “tumor,” used by Galen for “nerve bundle.” Of unknown origin; according to Galen, the proper sense of the word was “anything gathered into a ball.” (etymonline.com)