Parts of the brain rich in nerve cell bodies, hence appearing grey to the naked eye.

Those regions of the nervous system especially containing predominantly unmyelinated tissue and includes such regions as the cerebral cortex and areas such as cranial nerve nuclei and ganglia.

The grey, butterfly-shaped centre of the spinal cord that contains the cell bodies of neurons in the spinal cord.

Areas in the brain and spinal cord that consist of unmyelinated nerve cells. Unmyelinated nerve cells are those in which the long thread-like extensions are not covered in a layer of myelin – white, fatty, insulating material.

Tissue of the vertebrate central nervous system containing numerous nerve cell-bodies and dendrites and very large numbers of synapses. Occurs as a layer surrounding the central canal and also as a superficial layer ( cortex) on the cerebellum and cerebral hemispheres of higher vertebrates. This is the tissue of the neural nuclei or centres, such as the auditory cortex. Between these two layers of grey matter is a thick layer of white matter.

the grey nervous tissue of the brain and spinal cord consisting of the cell bodies and dendrites of nerve cells rather than the myelinated axons.