cortex

What it means

1. countableanatomyThe outer layer of an internal organ or body structure, such as the kidney or the brain.

   1 more example

   In the study, led by Ryota Kanai of the University College London, people who identified themselves as liberals generally had a larger anterior cingulate cortex — a comma-shaped region near the front of the brain that is involved in decision-making. By contrast, those who identified as conservatives had larger amygdalas — almond-shaped structures that are linked with emotional learning and the processing of fear.

   2011 April 8, Amie Ninh, “Liberal vs. Conservative: Does the Difference Lie in the Brain?”, in TIME, archived from the original on 18 Jul 2025

2. uncountablebiologyThe tissue of a stem or root that lies inward from the epidermis, but exterior to the vascular tissue.
3. countableuncountablearchaeologyThe outer surface of a piece of flint.

Where it comes from

1. Proto-Indo-European*(s)ker-
2. Proto-Indo-European*(s)kert-
3. Proto-Indo-European*(s)kort-ek-s
4. Latincortex
5. Englishcortex

Borrowed from Latin cortex (“cork, bark”).