What is the meaning of mastered?

verb

• Be or become completely proficient or skilled in.
  • usage: "She mastered Japanese in less than two years"
  • synonyms: master, get the hang
• Get on top of; deal with successfully.
  • usage: "He overcame his shyness"
  • synonyms: overcome, get over, subdue, surmount, master
• Have dominance or the power to defeat over.
  • usage: "Her pain completely mastered her"; "The methods can master the problems"
  • synonyms: dominate, master
• Have a firm understanding or knowledge of; be on top of.
  • usage: "Do you control these data"
  • synonyms: master, control

adjective

• Understood perfectly.
  • usage: "had his algebra problems down"
  • synonyms: down, down pat