Pronunciation: (mas'tu-rē, mä'stu-), [key]
—pl. -ter•ies for 1-4.
1. command or grasp, as of a subject: a mastery of Italian.
2. superiority or victory: mastery over one's enemies.
3. the act of mastering.
4. expert skill or knowledge.
5. the state of being master; power of command or control.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.