add vs contribute

add

verb
  • To give by way of increased possession (to someone); to bestow (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 make an addition; to augment; to increase; to add 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. 

contribute

verb
  • To give something that is or becomes part of a larger whole. 

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