cortex An outer layer.

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.

cortex
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).

cortex In animal and plant anatomy, outer layer of a gland or tissue. Examples are the cortex of the adrenal glands; the renal cortex of a kidney; the cerebral cortex or outer layer of the brain; the cortical layers of tissue in plant roots and stems lying between the bark or epidermis and the hard wood or conducting tissues.

cortex An outer layer. In plants, tissue immediately below the epidermis but outside the vascular bundles.