aid vs foil

aid

noun
  • Something which helps; a material source of help. 

  • 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. 

  • 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. 

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

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

foil

noun
  • Anything that acts by contrast to emphasise the characteristics of something. 

  • Thin aluminium/aluminum (or, formerly, tin) used for wrapping food. 

  • A thin, transparent plastic material on which marks are made and projected for the purposes of presentation. See transparency. 

  • A very thin sheet of metal. 

  • A thin layer of metal put between a jewel and its setting to make it seem more brilliant. 

  • A very thin sword with a blunted (or foiled) tip 

  • In literature, theatre/theater, etc., a character who helps emphasize the traits of the main character and who usually acts as an opponent or antagonist, but can also serve as the sidekick of the protagonist. 

  • One of the incorrect answers presented in a multiple-choice test. 

  • A stylized flower or leaf. 

  • Failure when on the point of attainment; defeat; frustration; miscarriage. 

  • The track of an animal. 

verb
  • To expand a product of two or more algebraic expressions, typically binomials. 

  • To blunt; to dull; to spoil. 

  • To prevent (someone) from accomplishing something. 

  • To prevent (something) from being accomplished. 

  • To cover or wrap with foil. 

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