1. In vertebrates, the cerebral cortex is a layer of grey matter lying above each cerebral hemisphere (cerebellum) in the brain.
2. In Heliozoa, an outer sphere of ectoplasm, often greatly vacuolated.
3. In some sessile, aquatic invertebrates, a fibrous outer layer of the periderm.
4. In some Porifera (e.g. Calcarea), an outer surface consisting of a syncitium formed from the interconnecting pseudopodia of amoebas.
cor·tex / ˈkôrˌteks/ • n. (pl. -ti·ces / -təˌsēz/ ) Anat. the outer layer of the cerebrum (thecerebral cortex), composed of folded gray matter and playing an important role in consciousness. ∎ an outer layer of another organ or body part such as a kidney (therenal cortex), the cerebellum, or a hair. ∎ Bot. an outer layer of tissue immediately below the epidermis of a stem or root.DERIVATIVES: cor·ti·cal / ˈkôrtikəl/ adj.
1. (in botany) The tissue between the epidermis and the vascular system in plant stems and roots. It is composed of parenchyma cells and shows little or no structural differentiation. Cortex is produced by activity of the apical meristem. See also endodermis.
2. (in zoology) The outermost layer of tissue of various organs, including the adrenal glands (adrenal cortex), kidneys (renal cortex), and cerebral hemispheres (cerebral cortex).