See under nerve root.
Why Is The Word “Root” In “Root Beer”?Is root beer the world's most oddly named carbonated beverage ... we don't know, that award might go to 7-up, but we're going to explore the naming of this soft drink regardless. What, after all, is the root in root beer?
Origin of motor root
First recorded in 1830–40
Definition for motor root (2 of 2)
a nerve fiber bundle that emerges from either side of the spinal cord and joins with a complementary bundle to form each spinal nerve in the series of spinal nerves: the root at the rear of the spinal cord (dorsal root or sensory root) conveys sensations to the central nervous system, and the root at the front (ventral root or motor root) conveys impulses to the muscles.
Origin of nerve root
First recorded in 1875–80
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019