hairline vs piano

hairline

adj
  • very thin, as thin as a hair 

noun
  • A fishing line made from hair. 

  • The line along one's forehead where hair starts growing. 

  • A very thin line in writing, drawing, or typography. 

  • A very thin fissure. 

piano

adj
  • Soft, quiet. 

  • Gentle, soft, subdued. 

verb
  • To play the piano. 

  • To move (the fingers) up and down on, similar to the motions of a pianist playing the piano. 

  • To become softer and less intense. 

  • To equip with a piano. 

adv
  • softly, as a musical direction (abbreviated to p. in sheet music) 

noun
  • a percussive keyboard musical instrument, usually ranging over seven octaves, with white and black colored keys, played by pressing these keys, causing hammers to strike strings 

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