identification vs initials

identification

noun
  • The act of identifying (i.e., which one, which thing). 

  • The combination of identifying (which one, which thing) and validating the identity (proving or confirming it); identifying and authenticating viewed as a unitary concept in cognition. 

  • A feeling of support, sympathy, understanding, or belonging towards somebody or something. 

  • A particular instance of identifying something. 

  • A document or documents serving as evidence of a person's identity. 

  • The state of being identified. 

initials

noun
  • An abbreviation of a person's name, constructed by taking the initial letters of first, last, and sometimes middle name(s). See monogram 

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