1. a branch of a blood vessel or a nerve.

2. any of the large branches of a spinal nerve after it emerges from the spinal column, notably the anteriorly directed ventral ramus and the posteriorly directed dorsal ramus. These distribute motor and sensory nerve fibers to other, smaller nerves.

3. any of the short nerve branches that arise from the ventral ramus and communicate with sympathetic ganglia (see rami communicantes).