aid vs avail

aid

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

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

noun
  • 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. 

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

avail

verb
  • To promote; to assist. 

  • To turn to the advantage of. 

  • To provide; to make available; to use or take advantage of (an opportunity or available resource). 

  • To be of use or advantage; to answer or serve the purpose; to have strength, force, or efficacy sufficient to accomplish the object. 

  • To be of service to. 

noun
  • An advertising slot or package. 

  • Effect in achieving a goal or aim; purpose, use (now usually in negative constructions). 

  • A press avail. 

  • A readily available stock of oil. 

  • Non-binding notice of availability for work. 

  • Proceeds; profits from business transactions. 

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