noun:

1. The heart or inner part of a physical thing.
2. A tiny sample of organic material obtained by means of a fine-needle biopsy.
3. Used to designate the main and most diverse monophyletic group within a clade or taxonomic group.
4. The most important part of a thing; the essence.
5. The center or inner part of a space or area.
6. The bony process which forms the central axis of the horns in many animals.
7. A body of individuals; an assemblage.
8. Alternative form of cor: a former Hebrew and Phoenician unit of volume.
9. The central part of a protein's structure, consisting mostly of hydrophobic amino acids.
10. The central fissile portion of a fission weapon.
11. The inner part of a nuclear reactor, in which the nuclear reaction takes place.
12. A deposit paid by the purchaser of a rebuilt part, to be refunded on return of a used, rebuildable part, or the returned rebuildable part itself.
13. The set of feasible allocations that cannot be improved upon by a subset (a coalition) of the economy's agents.
14. An atomic nucleus plus inner electrons (i.e., an atom, except for its valence electrons).
15. A miner's underground working time or shift.
16. The material between surface materials in a structured composite sandwich material.
17. The portion of a mold that creates an internal cavity within a casting or that makes a hole in or through a casting.
18. A hollow cylindrical piece of cardboard around which a web of paper or plastic is wound.
19. A cylindrical sample of rock or other materials obtained by core drilling.
20. A piece of ferromagnetic material (e.g., soft iron), inside the windings of an electromagnet, that channels the magnetic field.
21. An individual computer processor, in the sense when several processors (called cores or CPU cores) are plugged together in one single integrated circuit to work as one (called a multi-core processor).
22. A disorder of sheep caused by worms in the liver.
23. Ellipsis of core memory; magnetic data storage.
24. The central part of a fruit, containing the kernels or seeds.
25. Acronym of corporate responsibility.

name:

1. Acronym of Center for Operations Research and Econometrics.
2. Acronym of Congress of Racial Equality.
3. Acronym of Computing Research and Education Association.
4. Acronym of Council on Rehabilitation Education.
5. A female given name from Ancient Greek.
6. The birth name of Persephone/Proserpina, the queen of the Underworld/Hades, and goddess of the seasons and of vegetation. She is the daughter of Zeus and Demeter, and the wife of Hades.
7. Obsolete form of Korah.
8. Acronym of Consortium for Oceanographic Research and Education.

verb:

1. To remove the core of an apple or other fruit.
2. To extract a sample with a drill.

adjective:

1. Forming the most important or essential part.