succor vs succour

succor

succour

noun
  • Aid or assistance in the form of military equipment and soldiers, especially reinforcements sent to support military action. 

  • Protection, refuge, shelter; (countable) a place providing such protection, refuge or shelter. 

  • Aid, assistance, or relief given to one in distress; ministration. 

verb
  • To give aid, assistance, or help. 

  • To provide aid or assistance in the form of military equipment and soldiers; in particular, for helping a place under siege. 

  • To protect, to shelter; to provide a refuge. 

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