audition, a trial performance, as by an actor, dancer, or musician, to demonstrate suitability or skill.
starring, the lead; the prominent part
role, a part or character played by an actor or actress.
diary, a daily record, usually private, esp. of the writer's own experiences, observations, feelings, attitudes, etc.
See Anne Frank: Definition and Much More from Answers.com
I didn't get the part means the actor didn't get the acting job.
All the best.
You may want to consider using a dictionary.
Student or Learner