core

1. The central part of fruit, containing the kernels or seeds.

   the core of an apple or quince

2. The heart or inner part of a physical thing
3. The center or inner part of a space or area

   the core of a square

4. The most important part of a thing; the essence.

   the core of a subject

5. The portion of a mold that creates an internal cavity within a casting or that makes a hole in or through a casting.
6. The bony process which forms the central axis of the horns in many animals.
7. Magnetic data storage.
8. 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 multi-core processor).

   I wanted to play a particular computer game, which required I buy a new computer, so while the game said it needed at least a dual-core processor, I wanted my computer to be a bit ahead of the curve, so I bought a quad-core.

9. The material between surface materials in a structured composite sandwich material.

   a floor panel with a Nomex honeycomb core

10. The inner part of a nuclear reactor in which the nuclear reaction takes place.
11. A piece of ferromagnetic material (i.e. soft iron), inside the windings of an electromagnet, that channels the magnetic field.
12. A disorder of sheep caused by worms in the liver.
13. A cylindrical sample of rock or other materials obtained by core drilling.
14. A tiny sample of organic material obtained by means of a fine-needle biopsy.
15. The central part of a protein structure consisting in mostly hydrophobic aminoacids.
16. The set of feasible allocations that cannot be improved upon by a subset (a coalition) of the economy's agents.
17. A hollow cylindrical piece of cardboard around which a web of paper or plastic is winded.
18. An atomic nucleus plus inner electrons (i.e. except valence electrons).

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

noun

A body of individuals; an assemblage.

noun

A miner's underground working time or shift.

noun

Various former units of volume, particularly:

noun

(machinery, marine) 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.