noun (n)

• becoming proficient in the use of something; having mastery of

  menjadi ahli dalam memakai sesuatu; mempunyai penguasaan daripada

  Example:
  His mastering the art of cooking took a long time.
  

  source: wordnet30
• the act of making a master recording from which copies can be made

  tindakan membuat salinan dari rekaman master yang dapat dibuat

  Example:
  He received a bill for mastering the concert and making 100 copies.
  

  source: wordnet30