(1)   A bar of magnetic material (as soft iron) that passes through a coil and serves to increase the inductance of the coil
(2)   The chamber of a nuclear reactor containing the fissile material where the reaction takes place
(3)   The choicest or most essential or most vital part of some idea or experience
"The gist of the prosecutor's argument"
"The heart and soul of the Republican Party"
"The nub of the story"
(4)   The central meaning or theme of a speech or literary work
(5)   A small group of indispensable persons or things
"Five periodicals make up the core of their publishing program"
(6)   An organization founded by James Leonard Farmer in 1942 to work for racial equality
(7)   The center of an object
"The ball has a titanium core"
(8)   The central part of the Earth
(9)   A cylindrical sample of soil or rock obtained with a hollow drill


(10)   Remove the core or center from
"Core an apple"


Probably from coeur, from "cor" meaning "heart".


  1. A body of individuals; an assemblage.
  2. A miner's underground working time or shift.
  3. A Hebrew dry measure; a cor or homer.
  4. The central part of fruit, containing the kernels or seeds; as, the core of an apple or quince.
  5. The heart or inner part of a thing, as of a column, wall, rope, of a boil, etc.
  6. The center or inner part, as of an open space; as, the core of a square.
  7. The most important part of a thing; the essence; as, the core of a subject.
  8. The portion of a mold that creates an internal cavity within a casting or that makes a hole in or through a casting.
  9. A disorder of sheep caused by worms in the liver.
  10. The bony process which forms the central axis of the horns in many animals.
  11. magnetic memory.
  12. One of several parts in a computer processor.
  13. 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. Said to be an acronym for Cash On REturn, but that may be a backronym.


  1. To remove the core (4) of an apple.
  2. To extract a sample with a drill.