mastering (Noun) — Becoming proficient in the use of something; having mastery of. ex. "his mastering the art of cooking took a long time"
mastering (Noun) — The act of making a master recording from which copies can be made. ex. "he received a bill for mastering the concert and making 100 copies"
mastering (Verb) — Be or become completely proficient or skilled in. ex. "She mastered Japanese in less than two years"
mastering (Verb) — Get on top of; deal with successfully. ex. "He mastered his shyness"
mastering (Verb) — Have dominance or the power to defeat over. ex. "Her pain completely mastered her" ex. "The methods can master the problems"
mastering (Verb) — Have a firm understanding or knowledge of; be on top of.