Also, strike pay dirt. Make a valuable discovery or large profit, as in We've been researching the source of that quotation for a month and we finally hit pay dirt in the Library of Congress. This idiom, from the mid-1800s, refers to a miner's finding gold or other precious metals while sifting soil.

What does it mean to hit pay dirt?

: to do, find, or get something that results in money or success The band hit pay dirt with their first single. The police struck pay dirt when a witness came forward with new information.

Where does the expression hit pay dirt come from?

The term pay dirt originated in the American Old West in the 1850s during the California Gold Rush. By the 1870s the term pay dirt was also used to refer to any method of striking it rich or discovering something valuable. The preferred spelling is two words, pay dirt, though paydirt is often used.