# mother lode

idiom

Source: https://englishreference.com/idiom/mother-lode
Updated: 2026-08-10

## Meaning

Any source of valuable or useful material.

## Examples

- This old library is a mother lode of information.
- After searching for hours, the researchers finally found a mother lode of data in the archives.
- The historian realized that the dusty collection of letters was a mother lode of insight into the lives of the city's founders.

## Origin

Probably a calque of Spanish veta madre (“mother lode”). (disputed)

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.