coalescing vs concatenation

coalescing

noun
  • coalescence 

concatenation

noun
  • The application of these series of links. 

  • A series of links united; a series or order of things depending on each other, as if linked together; a chain, a succession. 

  • The operation of joining multiple character strings. 

  • A character string formed by joining multiple character strings. 

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