patio vs terracing

patio

noun
  • A paved outside area, adjoining a house, used for dining or recreation. 

  • An inner courtyard typical of traditional houses in some regions of Spain. 

terracing

noun
  • A terraced structure. 

  • A series of terraces. 

  • A stand with a series of tiers. 

  • The formation of terraces. 

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