noun

1. the hard, central part of an apple, pear, etc., that contains the seeds
2. the central or innermost part of anything
3. the most important part, as of a matter, discussion, etc.; essence; pith
4. in foundry work, that part of a mold which forms the interior of a hollow casting
5. a cylindrical sample of earth strata, as of rock, soil, snow, or ice, that is removed from the ground or ocean floor by boring with a long hollow drill and used to study the various layers of material that were deposited over a long period of geologic time
6. the central region of a nuclear reactor that contains the fissile fuel, and usually, control rods, moderator, etc.
7. the wood center to which outer layers of veneer are attached
8. Chem. the nucleus together with the closed electron shells of an atom; kernel
9. Elec. a mass of magnetic material placed inside a wire coil, serving to channel and increase the strength of the magnetic field resulting from current in the coil
10. Geol. the central zone inside the earth that begins at a depth of c. 2,900 km (c. 1,800 mi): it is extremely hot and has a liquid outer part and a solid inner part that are thought to be composed of iron and nickel

Etymology: ME < OFr cor, prob. < L cor, heart

transitive verb cored, coring cor′·ing

adjective