boulder vs ingot

boulder

verb
  • To engage in bouldering. 

noun
  • A particle greater than 256 mm in diameter, following the Wentworth scale 

  • A large marble, in children's games. 

  • A session of bouldering; involvement in bouldering. 

  • A large mass of stone detached from the surrounding land. 

ingot

verb
  • To form (scraps of metal) into ingots. 

noun
  • A solid block of more or less pure metal, often but not necessarily bricklike in shape and trapezoidal in cross-section, the result of pouring out and cooling molten metal, often immediately after smelting from raw ore or alloying from constituents. 

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