telescoping vs truncation

telescoping

noun
  • The act of extending or contracting in the manner of a telescope. 

  • A telescopic action. 

  • Extending limited data to make up for gaps 

truncation

noun
  • The replacement of a solid angle by a plane, or a similar operation in other dimensions. 

  • The act of truncating or shortening (for example, words are shortened to form blend words or portmanteaus). 

  • The removal of the least significant digits from a decimal number. 

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