central vs medial

central

adj
  • Exerting its action towards the peripheral organs. 

  • Having or containing the centre of something. 

  • Being in the centre. 

  • Being very important, or key to something. 

noun
  • centre 

medial

adj
  • Pertaining to the inside; closer to the median plane of the body or the midline of an organ. 

  • Of or pertaining to the media and/or the areas of the wing next to it. 

  • (of a speech sound) In the middle of a word. 

  • Closer to the addressee. 

  • Of or pertaining to a mean or average. 

  • Pertaining to the middle layer of a blood vessel, to its tunica media. 

  • (of a consonant) Central: produced when air flows across the center of the mouth over the tongue. 

noun
  • One or more letters that occur in the middle of a word. 

  • Any of various things that occur in the middle. 

How often have the words central and medial occurred in a corpus of books? (source: Google Ngram Viewer )