aid vs stifle

aid

noun
  • The rider's use of hands, legs, voice, etc. to control the horse. 

  • Help; assistance; succor, relief. 

  • An historical subsidy granted to the crown by Parliament for an extraordinary purpose, such as a war effort. 

  • A helper; an assistant. 

  • An exchequer loan. 

  • Something which helps; a material source of help. 

  • A pecuniary tribute paid by a vassal to his feudal lord on special occasions. 

verb
  • To climb with the use of aids such as pitons. 

  • To provide support to; to further the progress of; to help; to assist. 

stifle

noun
  • The joint between the femur and tibia in the hind leg of various four-legged mammals, especially horses, corresponding to the knee in humans. 

  • An act or state of being stifled. 

  • A bone disease of this region. 

verb
  • To prevent (a breath, cough, or cry, or the voice, etc.) from being released from the throat. 

  • To make (something) unable to be heard by blocking it with some medium. 

  • To prevent (something) from being revealed; to conceal, to hide, to suppress. 

  • To cause (someone) difficulty in breathing, or a choking or gagging feeling. 

  • To feel smothered; to find it difficult to breathe. 

  • To cause (a dog, horse, or other four-legged mammal) to dislocate or sprain its stifle joint. 

  • To die of suffocation. 

  • To keep in, hold back, or repress (something). 

  • To make (an animal or person) unconscious or cause (an animal or person) death by preventing breathing; to smother, to suffocate. 

  • To treat (a silkworm cocoon) with steam as part of the process of silk production. 

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