early vs preliminary

early

adj
  • Having begun to occur; in its early stages. 

  • Near the start or beginning. 

  • Near the start of the day. 

  • At a time in advance of the usual or expected event. 

  • Arriving a time before expected; sooner than on time. 

  • Of a star or class of stars, hotter than the sun. 

adv
  • At a time before expected; sooner than usual. 

  • Soon; in good time; seasonably. 

noun
  • A shift (scheduled work period) that takes place early in the day. 

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 

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