Master

1. Someone who has control over something or someone. She works as a school master.
2. Highly skilled. He is a master carpenter.
3. Owner of a animal or slave. A good master should take care of their pets.
4. The captain of a merchant ship. The master ordered all hands on deck.
5. A university degree. He received a Master's degree in Engineering.
6. The original of a document or recording. We made copies of the master.
7. An expert at something. Mark Twain was a master of fiction.
8. To learn to a high degree of proficiency. It took her years to master the art of needlecraft.