preliminary

Adjective

• denoting an action or event preceding or in preparation for something more important; designed to orient or acquaint with a situation before proceeding
  • a preliminary investigation
    

Noun

• something that serves as a preceding event or introduces what follows
  • training is a necessary preliminary to employment
    
  • drinks were the overture to dinner
    

• a minor match preceding the main event

Related words

• Synonyms: 
  overture , prelude , prelim