introductory in WordNet English dictionary

1. serving as a base or starting point
   "a basic course in Russian"; "basic training for raw recruits"; "a set of basic tools"; "an introductory art course"
   basic  introductory 
   
2. serving to open or begin
   "began the slide show with some introductory remarks"
   introductory 
   
3. serving as an introduction or preface
   introductory  prefatorial  prefatory