canker vs wheal

canker

verb
  • To be or become diseased, or as if diseased, with canker; to grow corrupt; to become venomous. 

  • To infect or pollute; to corrupt. 

  • To affect as a canker; to eat away; to corrode; to consume. 

  • To waste away, grow rusty, or be oxidized, as a mineral. 

noun
  • An avian disease affecting doves, poultry, parrots and birds of prey, caused by Trichomonas gallinae. 

  • A region of dead plant tissue caused by such a disease. 

  • Anything which corrodes, corrupts, or destroys. 

  • A kind of wild rose; the dog rose. 

  • An obstinate and often incurable disease of a horse's foot, characterized by separation of the horny portion and the development of fungoid growths. Usually resulting from neglected thrush. 

  • A plant disease marked by gradual decay. 

  • A corroding or sloughing ulcer; especially a spreading gangrenous ulcer or collection of ulcers in or about the mouth. 

  • A worm or grub that destroys plant buds or leaves; cankerworm. 

wheal

verb
  • Synonym of wale. 

noun
  • A small raised swelling on the skin, often itchy, caused by a blow from a whip or an insect bite etc. 

  • A mine. 

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