soil, gravel, or ore that can be mined profitably.
Informal. any source of success or wealth; a fortunate discovery or profitable venture: After months of experimentation, the scientists finally hit pay dirt.
Football. end zone(def 1).
Origin of pay dirt
An Americanism dating back to 1855–60
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a deposit rich enough in minerals to be worth mining
strike pay dirt or hit pay dirt informal to achieve one's objective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Online Etymology Dictionary, © 2010 Douglas Harper