add vs append

add

verb
  • To make an addition; to augment; to increase; to add on. 

  • To append (e.g. a statement); to say further information; to add on. 

  • To summon minions or reinforcements. 

  • To combine elements of (something) into one quantity. 

  • To give by way of increased possession (to someone); to bestow (on). 

  • To join or unite (e.g. one thing to another, or as several particulars) so as to increase the number, augment the quantity, or enlarge the magnitude, or so as to form into one aggregate. 

  • To sum up; to put together mentally; to add up. 

  • To perform the arithmetical operation of addition. 

noun
  • The addition of a song to a station's playlist. 

  • An act or instance of adding. 

  • An additional enemy that joins a fight after the primary target. 

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 add and append occurred in a corpus of books? (source: Google Ngram Viewer )