gold‧mine , gold mine /ˈɡəʊldmaɪn $ ˈɡoʊld-/ noun [countable]

1. informal a business or activity that produces large profits:
The nightclub turned out to be a goldmine.

2. a place where gold is dug out from a hole in the ground

3. be sitting on a goldmine to own something very valuable, especially without realizing it

[TahlilGaran] Dictionary of Contemporary English ▲