kerning vs set-off

kerning

noun
  • The adjustment of the horizontal space between selected pairs of glyphs in a typeface. 

set-off

noun
  • An offset. 

  • That which is set off against another thing; an offset. 

  • A counterclaim; a cross debt or demand; a distinct claim filed or set up by the defendant against the plaintiff's demand. 

How often have the words kerning and set-off occurred in a corpus of books? (source: Google Ngram Viewer )