core in WordNet English dictionary

1. the central meaning or theme of a speech or literary work
   effect  essence  burden  core  gist 
   
2. 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"
   kernel  substance  core  center  centre  essence  gist  heart  heart and soul  inwardness  marrow  meat  nub  pith  sum  nitty-gritty 
   
3. a bar of magnetic material (as soft iron) that passes through a coil and serves to increase the inductance of the coil
   core 
   
4. the chamber of a nuclear reactor containing the fissile material where the reaction takes place
   core 
   
5. (computer science) a tiny ferrite toroid formerly used in a random access memory to store one bit of data; now superseded by semiconductor memories
   "each core has three wires passing through it, providing the means to select and detect the contents of each bit"
   core  magnetic core 
   
6. a small group of indispensable persons or things
   "five periodicals make up the core of their publishing program"
   core  nucleus  core group 
   
7. the center of an object
   "the ball has a titanium core"
   core 
   
8. the central part of the Earth
   core 
   
9. a cylindrical sample of soil or rock obtained with a hollow drill
   core 
   

1. remove the core or center from
   "core an apple"
   core