backdrop vs terrain

backdrop

noun
  • A decorated cloth hung at the back of a stage. 

  • An image that serves as a visual background. 

  • The setting or background of an acted performance. 

  • Any background situation. 

verb
  • To serve as a backdrop for. 

terrain

noun
  • The surface of the earth; the ground. 

  • A single, distinctive rock formation; an area having a preponderance of a particular rock or group of rocks. 

  • An area of land or the particular features of it. 

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