stain vs tar

stain

verb
  • To discolour. 

  • To cause to seem inferior or soiled by comparison. 

  • To coat a surface with a stain 

  • To treat (a microscopic specimen) with a dye, especially one that dyes specific features 

  • To taint or tarnish someone's character or reputation 

  • To become stained; to take a stain. 

noun
  • A reagent or dye used to stain microscope specimens so as to make some structures visible. 

  • A discoloured spot or area. 

  • Any of a number of non-standard tinctures used in modern heraldry. 

  • A blemish on one's character or reputation. 

  • A substance used to soak into a surface and colour it. 

tar

verb
  • To besmirch. 

  • To create a tar archive. 

  • To coat with tar. 

noun
  • A file produced by such a program. 

  • A black, oily, sticky, viscous substance, consisting mainly of hydrocarbons derived from organic materials such as wood, peat, or coal. 

  • A Persian long-necked, waisted string instrument, shared by many cultures and countries in the Middle East and the Caucasus. 

  • A solid residual byproduct of tobacco smoke. 

  • A single-headed round frame drum originating in North Africa and the Middle East. 

  • Black tar, a form of heroin. 

  • Coal tar. 

  • A program for archiving files, common on Unix systems. 

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