rowhouse vs terracing

rowhouse

noun
  • One of a row of houses situated side by side and sharing a common wall. 

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 rowhouse and terracing occurred in a corpus of books? (source: Google Ngram Viewer )