mother lode

or moth·er·lode

[ muhth-er-lohd ]

noun

1. Mining. a rich or important lode.
2. a major or profitable source or supply:

   New York City is a mother lode of actors.

mother lode

noun

1. mining the principal lode in a system

Word History and Origins

Origin of mother lode¹

First recorded in 1855–60

Example Sentences

Despite California’s sapphire tilt, the state’s donors are the mother lode of campaign cash for both parties.

From Los Angeles Times

But it could be a mother lode for small and large local news outlets, providing $500 million a year to preserve and grow local newsrooms.

From Seattle Times

But for a noir of isolation and concealment, about how the past can often feel inescapable, these shadowy dugouts — Travis’ motel, a church and one character’s lonely lair — are an atmospheric mother lode.

From Los Angeles Times

Two-thousand-five-hundred miles west of Dodger Stadium was a mother lode of Dodgers memorabilia.

From Los Angeles Times

The encyclopedia was crucial not only because it’s free and accessible, but also because it contains a mother lode of facts and so much of its material is consistently formatted.

From New York Times