noun
nerve cord
Anatomical term for a cord-like bundle of nerve fibers, such as the ventral nerve cord in invertebrates or the spinal cord in vertebrates.
昆虫の腹側には神経索が走っている。
A nerve cord runs along the ventral side of insects.
脊髄 refers specifically to the spinal cord in vertebrates, while 神経索 is a broader anatomical term for any nerve cord, including those in invertebrates.
Compound of 神経 (nerve) and 索 (cord, rope). The term is a direct translation of the English 'nerve cord' used in anatomy.