<p><strong>Noun:</strong></p><ul><li>the outer region of an organ or structure, as the outer portion of the kidney.</li><li>the cerebral cortex.</li><li>the portion of a stem between the epidermis and the vascular tissue; bark.</li><li>any outer layer, as rind.</li><li>the surface tissue layer of a fungus or lichen, composed of massed hyphal cells.</li></ul>