impost vs springer

impost

noun
  • The top part of a column, pillar, pier, wall, etc. that supports an arch. 

  • The weight that must be carried by a horse in a race, the handicap. 

  • A tax, tariff or duty that is imposed, especially on merchandise. 

springer

noun
  • A stone at the base of an arch (from which the arch springs). 

  • A springer spaniel. 

  • A person that springs. 

  • A springbok. 

  • A spring salmon. 

  • A springing cow. 

  • Anything that springs. 

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