Mine (noun)

1. A excavation in the earth from which minerals are extracted.
2. A deposit of valuable minerals in the earth's crust.
3. A source of something valuable or useful.
4. A type of weapon that is placed underground and detonated by remote control when an enemy vehicle, person, or structure passes over or near it.
5. Something that is owned or controlled by a particular person or group.

Origin:

Middle english, from old english mīne; akin to old high german mīna mine, latin meus, greek mou.

Examples:

1. The miners went down into the coal mine every day.
2. There's a gold mine in the hills.
3. She struck oil, and now she's a millionaire.
4. The enemy soldiers triggered a mine and several of them were killed.
5. This computer is my mine, I won't let you use it.