/ ˈgæŋgliən; NAmE / noun ( pl. gan·glia / -liə; NAmE /) ( medical )
1.
a mass of nerve cells
2.
a swelling in a tendon , often at the back of the hand
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WORD ORIGIN
late 17th cent.: from Greek ganglion tumour on or near sinews or tendons, used by Galen to denote the complex nerve centres.