preliminary vs provisional

preliminary

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

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

  • A preparation for a main matter; an introduction. 

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

provisional

noun
  • A postage stamp issued locally before an official issue is released. 

  • An interim denture. 

adj
  • Temporary, but with the intention of eventually becoming permanent or being replaced by a permanent equivalent. 

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