central vs umbilical

central

adj
  • Having or containing the centre of something. 

  • Being in the centre. 

  • Exerting its action towards the peripheral organs. 

  • Being very important, or key to something. 

noun
  • centre 

umbilical

adj
  • Of, or relating to, the navel (umbilicus) or the umbilical cord. 

  • Such that the curvatures of normal sections are all equal to each other. 

noun
  • A cord connecting an astronaut to a spacecraft, or a craft to ground control prior to launch, etc. 

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