build up vs cumulate

build up

verb
  • To accumulate, to pile up, to increase in stages. 

  • To close up by building. 

  • To strengthen. 

  • In solitaire card games, to place a card over another card of lower value. (e.g., place 5♦ over 4♣) 

  • To erect; to construct. 

cumulate

verb
  • To accumulate; to amass. 

  • To be accumulated. 

noun
  • An igneous rock formed by the accumulation of crystals from a magma either by settling or floating. 

adj
  • accumulated, agglomerated, amassed 

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