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from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A geologically occurring slow fission reactor, especially in the Earth's past.
  • n. Any man-made industrial structure built into the Earth's crust and operating on the principle of nuclear fission.
  • n. The theorized natural fission reactor at the center of the Earth which would account for the geomagnetic field.


From the prefix geo- meaning “Earth”, and reactor, a term in nuclear physics (Wiktionary)



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