Zeppelin vs airship

Zeppelin

noun
  • A type of large dirigible rigid airship of the early 20th century, built by the German Luftschiffbau Zeppelin and designed to carry passengers or bombs. 

  • A rigid airship dirigible, not restricted to Germany nor the early 20th century. 

name
  • A German manufacturing company, famed for building the zeppelin airships. 

airship

noun
  • A police air unit, a police helicopter 

  • A lighter-than-air aircraft that can be propelled forward through the air as well as steered. 

  • Any aircraft. 

  • A high ranking official of the RAF, viewed as arrogant and distant. 

verb
  • To transport goods by aircraft. 

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