integration vs smelting

integration

noun
  • The act or process of making whole or entire. 

  • The process of fitting into a community, notably applied to minorities. 

  • The operation of finding the integral of a function. 

  • In evolution, the process by which the manifold is compacted into the relatively simple and permanent; supposed to alternate with differentiation as an agent in species' development. 

  • The process of combining with compatible elements in order to incorporate them. 

smelting

noun
  • The process of melting or fusion, especially to extract a metal from its ore. 

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