What is the meaning of starter?

noun

• An electric motor for starting an engine.
  • synonyms: starter motor, starting motor
• A contestant in a team sport who is in the game at the beginning.
• The official who signals the beginning of a race or competition.
  • synonyms: dispatcher
• Any new participant in some activity.
  • synonyms: newcomer, fledgling, fledgeling, neophyte, freshman, newbie, entrant
• Food or drink to stimulate the appetite (usually served before a meal or as the first course.
  • synonyms: appetizer, appetiser
• A hand tool consisting of a rotating shaft with parallel handle.
  • synonyms: crank
• A culture containing yeast or bacteria that is used to start the process of fermentation or souring in making butter or cheese or dough.
  • usage: "to make sourdough you need a starter"