adhere vs append

adhere

verb
  • To be attached or devoted by personal union, in belief, on principle, etc. 

  • To affirm a judgment. 

  • To be consistent or coherent; to be in accordance; to agree. 

  • To stick fast or cleave, as a glutinous substance does; to become joined or united. 

append

verb
  • To add, as an accessory to the principal thing; to annex 

  • To write more data to the end of a pre-existing file, string, or other object. 

  • To hang or attach to, as by a string, so that the thing is suspended 

noun
  • An instance of writing more data to the end of an existing file. 

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