automobile vs hardtop

automobile

noun
  • A type of vehicle designed to move on the ground under its own stored power and intended to carry a driver, a small number of additional passengers, and a very limited amount of other load. A car or motorcar. 

adj
  • Self-moving; self-propelled. 

hardtop

noun
  • The removable rigid roof of a convertible or sports car. 

  • An indoor cinema with a roof, as opposed to a drive-in. 

  • A car with such a roof. 

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