pavement vs underfloor

pavement

noun
  • A paved surface; a hard covering on the ground. 

  • A paving (paved part) of a road or other thoroughfare; the roadway or road surface. 

  • The interior flooring of a church sanctuary, between the communion rail and the altar. 

  • The paved part of an area other than a road or sidewalk, such as a cobblestone plaza, asphalt schoolyard or playground, or parking lot. 

  • A paved path, for the use of pedestrians, located at the side of a road. 

underfloor

noun
  • A layer of flooring beneath the main floor surface. 

adj
  • Located beneath the floor. 

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