experimental vs preliminary

experimental

noun
  • The subject of an experiment. 

adj
  • Pertaining to or founded on experiment. 

  • Experiential, empirical. 

  • Serving to be experimented upon; used in an experiment. 

  • Serving as an experiment; serving to experiment. 

preliminary

noun
  • A preparation for a main matter; an introduction. 

  • Any of a series of sports events that determine the finalists 

  • A relatively minor contest that precedes a major one, especially in boxing 

adj
  • In preparation for the main matter; initial, introductory, preparatory. 

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