from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The main vein of ore in a region.
- n. An abundant or rich source: "the kind . . . who makes Boston the mother lode of advance men” ( David Nyhan).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A large or rich vein of gold or of another precious mineral from which other branches extend.
- n. Any source of valuable or useful material.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the main vein of ore in a deposit
Probably from Spanish veta madre ("mother lode") (Wiktionary)